• Re: The reality of sets, on a scale of 1 to 10 [Was: The non-existence

    From Moebius@21:1/5 to All on Fri Mar 21 20:46:59 2025
    Am 21.03.2025 um 20:37 schrieb Moebius:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more
    reality than the even positive numbers. He said that is not in
    conflict with the identical cardinality of both
    sets. And he was right!


    I doubt very much Cantor said such rubbish.

    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality. (I'd dare to bet
    that this was the only time he ever used that phrase in this context.)

    Her's the original quote:

    "Sei M die Gesamtheit (nü) aller endlichen Zahlen nü, M' die
    Gesamtheit (2nü) aller geraden Zahlen 2nü. Hier ist unbedingt richtig, daß
    M seiner Entität nach /reicher/ ist, als M'; enthält doch M außer den geraden Zahlen, aus welchen M' besteht, noch außerdem alle ungeraden
    Zahlen M''. Andererseits ist ebenso unbedingt richtig, daß den beiden
    Mengen M und M' nach Nr. 2 und 3 /dieselbe/ Kardinalzahl zukommt. Beides
    ist sicher und keines steht dem andern im Wege, wenn man nur auf die Distinktion von /Realität/ und /Zahl/ achtet. Man muß also sagen: /die
    Menge M hat mehr Realität wie M', weil sie M' und außerdem M'' als Bestandteile enthält; die den beiden Mengen M und M' zukommenden Kardinalzahlen sind aber gleich/." (G. Cantor)

    Google Translator:

    "Let M be the totality (nu) of all finite numbers nu, and M' the
    totality (2nu) of all even numbers 2nu. Here it is absolutely true that
    M is /richer/ than M' in its essence [entity]; after all, M contains, in addition to the even numbers of which M' consists, all the odd numbers
    M''. On the other hand, it is equally absolutely true that the two sets
    M and M', according to no. 2 and 3, have /the same/ cardinal number.
    Both are certain, and neither precludes the other, if one only pays
    attention to the distinction between /reality/ and /number/. One must
    therefore say: /the set M has more reality than M' because it contains
    M' and, in addition, M'' as components; but the cardinal numbers
    belonging to the two sets M and M' are equal/."

    Hint: WM is all about words.

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  • From Moebius@21:1/5 to All on Fri Mar 21 20:51:55 2025
    Am 21.03.2025 um 20:46 schrieb Moebius:
    Am 21.03.2025 um 20:37 schrieb Moebius:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more
    reality than the even positive numbers. He said that is not in
    conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.

    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality. (I'd dare to bet
    that this was the only time he ever used that phrase in this context.)

    Her's the original quote:

    "Sei M die Gesamtheit (nü) aller endlichen Zahlen nü, M' die
    Gesamtheit (2nü) aller geraden Zahlen 2nü. Hier ist unbedingt richtig, daß M seiner Entität nach /reicher/ ist, als M'; enthält doch M außer den geraden Zahlen, aus welchen M' besteht, noch außerdem alle ungeraden
    Zahlen M''. Andererseits ist ebenso unbedingt richtig, daß den beiden
    Mengen M und M' nach Nr. 2 und 3 /dieselbe/ Kardinalzahl zukommt. Beides
    ist sicher und keines steht dem andern im Wege, wenn man nur auf die Distinktion von /Realität/ und /Zahl/ achtet. Man muß also sagen: /die Menge M hat mehr Realität wie M', weil sie M' und außerdem M'' als Bestandteile enthält; die den beiden Mengen M und M' zukommenden Kardinalzahlen sind aber gleich/." (G. Cantor)

    Google Translator:

    "Let M be the totality (nu) of all finite numbers nu, and M' the
    totality (2nu) of all even numbers 2nu. Here it is absolutely true that
    M is /richer/ than M' in its essence [entity]; after all, M contains, in addition to the even numbers of which M' consists, all the odd numbers
    M''. On the other hand, it is equally absolutely true that the two sets
    M and M', according to no. 2 and 3, have /the same/ cardinal number.
    Both are certain, and neither precludes the other, if one only pays
    attention to the distinction between /reality/ and /number/. One must therefore say: /the set M has more reality than M' because it contains
    M' and, in addition, M'' as components; but the cardinal numbers
    belonging to the two sets M and M' are equal/."

    Well, what can we say? Set theory in its infancy.

    Hint: WM is all about words.


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  • From Moebius@21:1/5 to All on Fri Mar 21 20:37:15 2025
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive numbers have more
    reality than the even positive numbers.
    He said that is not in conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.
    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality. (I'd dare to bet
    that this was the only time he ever used that phrase in this context.)

    Hint: WM is all about words.

    --- SoupGate-Win32 v1.05
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  • From Moebius@21:1/5 to All on Fri Mar 21 22:10:43 2025
    Am 21.03.2025 um 20:51 schrieb Moebius:
    Am 21.03.2025 um 20:46 schrieb Moebius:
    Am 21.03.2025 um 20:37 schrieb Moebius:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more
    reality than the even positive numbers. He said that is not in
    conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.

    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset
    of IN, while both sets still have the same cardinality. (I'd dare to
    bet that this was the only time he ever used that phrase in this
    context.)

    Her's the original quote:

    "Sei M die Gesamtheit (nü) aller endlichen Zahlen nü, M' die
    Gesamtheit (2nü) aller geraden Zahlen 2nü. Hier ist unbedingt richtig,
    daß
    M seiner Entität nach /reicher/ ist, als M'; enthält doch M außer den
    geraden Zahlen, aus welchen M' besteht, noch außerdem alle ungeraden
    Zahlen M''. Andererseits ist ebenso unbedingt richtig, daß den beiden
    Mengen M und M' nach Nr. 2 und 3 /dieselbe/ Kardinalzahl zukommt. Beides
    ist sicher und keines steht dem andern im Wege, wenn man nur auf die
    Distinktion von /Realität/ und /Zahl/ achtet. Man muß also sagen: /die
    Menge M hat mehr Realität wie M', weil sie M' und außerdem M'' als
    Bestandteile enthält; die den beiden Mengen M und M' zukommenden
    Kardinalzahlen sind aber gleich/." (G. Cantor)

    Google Translator:

    "Let M be the totality (nu) of all finite numbers nu, and M' the
    totality (2nu) of all even numbers 2nu. Here it is absolutely true
    that M is /richer/ than M' in its essence [entity]; after all, M
    contains, in addition to the even numbers of which M' consists, all
    the odd numbers M''. On the other hand, it is equally absolutely true
    that the two sets M and M', according to no. 2 and 3, have /the same/
    cardinal number. Both are certain, and neither precludes the other, if
    one only pays attention to the distinction between /reality/ and /
    number/. One must therefore say: /the set M has more reality than M'
    because it contains M' and, in addition, M'' as components; but the
    cardinal numbers belonging to the two sets M and M' are equal/."

    Well, what can we say? Set theory in its infancy.

    Moreover, Cantor wasn't THAT good as a philosopher of mathematics. Frege
    was MUCH better.

    Hint: WM is all about words.

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  • From Alan Mackenzie@21:1/5 to Moebius on Fri Mar 21 21:25:29 2025
    Moebius <invalid@example.invalid> wrote:
    Am 21.03.2025 um 20:37 schrieb Moebius:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more
    reality than the even positive numbers. He said that is not in
    conflict with the identical cardinality of both
    sets. And he was right!


    I doubt very much Cantor said such rubbish.

    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality. (I'd dare to bet
    that this was the only time he ever used that phrase in this context.)

    Her's the original quote:

    "Sei M die Gesamtheit (nü) aller endlichen Zahlen nü, M' die
    Gesamtheit (2nü) aller geraden Zahlen 2nü. Hier ist unbedingt richtig, daß M seiner Entität nach /reicher/ ist, als M'; enthält doch M außer den geraden Zahlen, aus welchen M' besteht, noch außerdem alle ungeraden
    Zahlen M''. Andererseits ist ebenso unbedingt richtig, daß den beiden
    Mengen M und M' nach Nr. 2 und 3 /dieselbe/ Kardinalzahl zukommt. Beides
    ist sicher und keines steht dem andern im Wege, wenn man nur auf die Distinktion von /Realität/ und /Zahl/ achtet. Man muß also sagen: /die Menge M hat mehr Realität wie M', weil sie M' und außerdem M'' als Bestandteile enthält; die den beiden Mengen M und M' zukommenden Kardinalzahlen sind aber gleich/." (G. Cantor)

    What was the context of this quote? Was it a letter to a fellow
    mathematician, or a in a published work, or what?

    It seems Cantor was fumbling around, trying to get a handle on some
    concept, and called it Realität for want of a better word. With the
    benefit of over a century of development, we can see there is no need for
    this concept, which might not even be consistent.

    OK, Cantor said/wrote this. It is still rubbish from a modern point of
    view. It is only to be expected that the pioneers of a new field, along
    with valid developments, also make mistakes. "Potential infinity" was
    another such mistake. We should accept that there were falsehoods among
    these original ideas, and disregard those falsehoods today. The Boeing aircraft company does not rely any more on calculations made by the
    Wright brothers way back when. Neither should we pretend that Cantor was
    an infallible god when it comes to set theory.

    Google Translator:

    "Let M be the totality (nu) of all finite numbers nu, and M' the
    totality (2nu) of all even numbers 2nu. Here it is absolutely true that
    M is /richer/ than M' in its essence [entity]; after all, M contains, in addition to the even numbers of which M' consists, all the odd numbers
    M''. On the other hand, it is equally absolutely true that the two sets
    M and M', according to no. 2 and 3, have /the same/ cardinal number.
    Both are certain, and neither precludes the other, if one only pays attention to the distinction between /reality/ and /number/. One must therefore say: /the set M has more reality than M' because it contains
    M' and, in addition, M'' as components; but the cardinal numbers
    belonging to the two sets M and M' are equal/."

    Hint: WM is all about words.

    Yes.

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Fri Mar 21 23:15:52 2025
    Am 21.03.2025 um 22:25 schrieb Alan Mackenzie:
    Moebius <invalid@example.invalid> wrote:
    Am 21.03.2025 um 20:37 schrieb Moebius:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more
    reality than the even positive numbers. He said that is not in
    conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.

    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality. (I'd dare to bet
    that this was the only time he ever used that phrase in this context.)

    Her's the original quote:

    "Sei M die Gesamtheit (nü) aller endlichen Zahlen nü, M' die
    Gesamtheit (2nü) aller geraden Zahlen 2nü. Hier ist unbedingt richtig, daß
    M seiner Entität nach /reicher/ ist, als M'; enthält doch M außer den
    geraden Zahlen, aus welchen M' besteht, noch außerdem alle ungeraden
    Zahlen M''. Andererseits ist ebenso unbedingt richtig, daß den beiden
    Mengen M und M' nach Nr. 2 und 3 /dieselbe/ Kardinalzahl zukommt. Beides
    ist sicher und keines steht dem andern im Wege, wenn man nur auf die
    Distinktion von /Realität/ und /Zahl/ achtet. Man muß also sagen: /die
    Menge M hat mehr Realität wie M', weil sie M' und außerdem M'' als
    Bestandteile enthält; die den beiden Mengen M und M' zukommenden
    Kardinalzahlen sind aber gleich/." (G. Cantor)

    What was the context of this quote? Was it a letter to a fellow mathematician, or a in a published work, or what?

    I really don't know (can't tell).

    It seems Cantor was fumbling around, trying to get a handle on some
    concept, and called it Realität for want of a better word.

    Indeed. As I said: "Set theory in its infancy."

    "Substance" might have worked too, imho. :-P

    With the benefit of over a century of development, we can see there is no need for
    this concept, which might not even be consistent.

    Right.

    OK, Cantor said/wrote this. It is still rubbish from a modern point of
    view. It is only to be expected that the pioneers of a new field, along
    with valid developments, also make mistakes.

    Again: "Moreover, Cantor wasn't THAT good as a philosopher of
    mathematics. Frege was MUCH better."

    BUT: The notion of "potential infinity" was not invented by Cantor or
    his contemporaries, actually it goes back to _Aristotle_. Cantor just
    voted for the (existence of the) actual infinite as represented by his
    infinite sets.

    "Cantor's work was well received by some of the prominent mathematicians
    of his day, such as Richard Dedekind. But his willingness to regard
    infinite sets as objects to be treated in much the same way as finite
    sets was bitterly attacked by others, particularly Kronecker. There was
    no objection to a 'potential infinity' in the form of an unending
    process, but an 'actual infinity' in the form of a completed infinite
    set was harder to accept."

    [H.B. Enderton: "Elements of set theory", Academic Press, New York
    (1977) p. 14f]

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  • From WM@21:1/5 to Moebius on Sat Mar 22 09:47:22 2025
    On 21.03.2025 20:37, Moebius wrote:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more
    reality than the even positive numbers. He said that is not in
    conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.
    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality.

    This proves that cardinality does not concern quantities but only judges
    the behaviour of potentially infinite sets: They go on and on. Every
    pair of a bijection has infinitely may successors. A final
    quantification is impossible.

    (I'd dare to bet
    that this was the only time he ever used that phrase in this context.)

    You would win.

    Hint: WM is all about words.

    Reality is more than words.

    Regards, WM

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  • From WM@21:1/5 to Moebius on Sat Mar 22 10:10:45 2025
    On 21.03.2025 23:15, Moebius wrote:

    "Substance" might have worked too, imho. :-P

    Yes, perhaps that is a better term. It shows that there is more to be
    measured.

    BUT: The notion of "potential infinity" was not invented by Cantor or
    his contemporaries, actually it goes back to _Aristotle_. Cantor just
    voted for the (existence of the) actual infinite as represented by his infinite sets

    as including the potential infinity. Correct. ℕ contains |ℕ|_def.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Sat Mar 22 10:03:32 2025
    On 21.03.2025 22:25, Alan Mackenzie wrote:


    What was the context of this quote? Was it a letter to a fellow mathematician, or a in a published work, or what?

    A published work: Mitteilungen zur Lehre vom Transfiniten. Collected
    Works 378-439.

    It seems Cantor was fumbling around, trying to get a handle on some
    concept, and called it Realität for want of a better word. With the
    benefit of over a century of development, we can see there is no need for this concept, which might not even be consistent.

    Uneducated cranks may think so. Reality however is the fact that proper
    subsets have fewer elements than their sets.

    OK, Cantor said/wrote this. It is still rubbish from a modern point of
    view.

    The modern point of view is supported by fools only, mainly by
    uneducated poor thinkers.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Sat Mar 22 09:43:39 2025
    On 21.03.2025 19:48, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 21.03.2025 18:39, Jim Burns wrote:
    On 3/21/2025 3:50 AM, WM wrote:
    On 20.03.2025 23:25, Jim Burns wrote:

    For sets not.having a WM.size,
    Bob vanishing isn't a size.change.

    Only if reducing isn't reducing.

    What you (WM) think is reducing
    isn't reducing.

    You confuse the clear fact that in the reality of sets vanishing means
    reducing with the foolish claim that cardinality was a meaningful notion.

    Learn that even Cantor has accepted that the positive numbers have more
    reality than the even positive numbers.

    You mean something like positive numbers have a reality score of 5, and
    the even positive numbers only have a reality score of 3?

    No, The number of positive numbers is |ℕ|. The number of even natural
    numbers is |ℕ|/2. It needs really years of brainwashing to honestly
    believe that addition of a number or subset leaves the number of
    elements unchanged. It leaves the cardinality unchanged because this
    notion is tantamount to potential infinity.

    He said that is not in conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.

    You have pronounced your own sentence: Your opinions are rubbish.

    He was a mathematician.

    And you are not at all educated in this field.

    "Coun[t]able" is simply another name for potential infinity.

    Not even close.

    You are simply unable to follow reasonable ideas.

    Therefore the sentence "What you (WM) think is reducing isn't
    reducing" exhibits you as a snooty dilettante who cannot distinguish
    between cardinality and reality.

    Hah! He's got to you, has he?

    No, that is my judgement on JB.

    Regards, WM

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  • From Ralf Bader@21:1/5 to Moebius on Sat Mar 22 09:34:07 2025
    On 03/21/2025 11:15 PM, Moebius wrote:
    Am 21.03.2025 um 22:25 schrieb Alan Mackenzie:

    What was the context of this quote? Was it a letter to a fellow
    mathematician, or a in a published work, or what?

    I really don't know (can't tell).

    It is from
    4. Mitteilungen zur Lehre vom Transfiniten. VIII Nr. 7/8. 417
    (the header of page 417 in his Gesammelte Abhandlungen)
    Where did you take this quote from?

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  • From joes@21:1/5 to All on Sat Mar 22 11:25:48 2025
    Am Sat, 22 Mar 2025 09:47:22 +0100 schrieb WM:
    On 21.03.2025 20:37, Moebius wrote:
    Am 21.03.2025 um 19:48 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Learn that [...] Cantor [once] has [uttered] that the positive
    numbers have more reality than the even positive numbers. He said
    that is not in conflict with the identical cardinality of both sets.
    And he was right!
    I doubt very much Cantor said such rubbish.
    Actually, WM is right here. But the notion of "more reality" clearly
    wasn't meant as a technical term (by Cantor). He -Cantor- was just
    trying to explain the mathematical fact that 2IN is a PROPER subset of
    IN, while both sets still have the same cardinality.
    Yeah, one can just talk about subsets, and nobody disputes that.

    This proves that cardinality does not concern quantities but only judges
    the behaviour of potentially infinite sets: They go on and on. Every
    pair of a bijection has infinitely may successors. A final
    quantification is impossible.
    No, there are also finite cardinalities, and "actually infinite" sets
    like N also have a cardinality (all infinite sets go "on and on").
    A bijection doesn't have to be ordered. What do you mean by
    "quantification"?

    (I'd dare to bet that this was the only time he ever used that phrase
    in this context.)
    You would win.
    Then you shouldn't abuse "reality" like that.

    Hint: WM is all about words.
    Reality is more than words.
    *facepalm*

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Sat Mar 22 11:31:18 2025
    Am Sat, 22 Mar 2025 09:43:39 +0100 schrieb WM:
    On 21.03.2025 19:48, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 21.03.2025 18:39, Jim Burns wrote:
    On 3/21/2025 3:50 AM, WM wrote:
    On 20.03.2025 23:25, Jim Burns wrote:

    For sets not.having a WM.size, Bob vanishing isn't a size.change.
    Only if reducing isn't reducing.
    What you (WM) think is reducing isn't reducing.
    You confuse the clear fact that in the reality of sets vanishing means
    reducing with the foolish claim that cardinality was a meaningful
    notion.
    Learn that even Cantor has accepted that the positive numbers have
    more reality than the even positive numbers.
    You mean something like positive numbers have a reality score of 5, and
    the even positive numbers only have a reality score of 3?
    No, The number of positive numbers is |ℕ|. The number of even natural numbers is |ℕ|/2. It needs really years of brainwashing to honestly
    believe that addition of a number or subset leaves the number of
    elements unchanged. It leaves the cardinality unchanged because this
    notion is tantamount to potential infinity.
    Aaand those numbers are equally infinite. You just never learned that
    for infinite sets "reality" and cardinality don't have to correspond.

    "Coun[t]able" is simply another name for potential infinity.
    Not even close.
    You are simply unable to follow reasonable ideas.
    "Countable" means finite or bijective to N.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Sat Mar 22 14:04:12 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 21.03.2025 19:48, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 21.03.2025 18:39, Jim Burns wrote:
    On 3/21/2025 3:50 AM, WM wrote:
    On 20.03.2025 23:25, Jim Burns wrote:

    For sets not.having a WM.size,
    Bob vanishing isn't a size.change.

    Only if reducing isn't reducing.

    What you (WM) think is reducing
    isn't reducing.

    You confuse the clear fact that in the reality of sets vanishing
    means reducing with the foolish claim that cardinality was a
    meaningful notion.

    Learn that even Cantor has accepted that the positive numbers have
    more reality than the even positive numbers.

    You mean something like positive numbers have a reality score of 5,
    and the even positive numbers only have a reality score of 3?

    No, The number of positive numbers is |ℕ|. The number of even natural numbers is |ℕ|/2.

    Hahaha!

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16, ....}
    and {1, 3, 5, 7, 9, ....}?

    The mathematically correct answer is that they are both the same size (cardinality) because there is a bijection between them. You don't
    understand this, so I expect you not to answer the question.

    It needs really years of brainwashing to honestly believe that addition
    of a number or subset leaves the number of elements unchanged.

    No, it just takes mathematical education, which you lack.

    It leaves the cardinality unchanged because this notion is tantamount
    to potential infinity.

    You're stuck in the 1880s.

    He said that is not in conflict with the identical cardinality of both
    sets. And he was right!

    I doubt very much Cantor said such rubbish.

    You have pronounced your own sentence: Your opinions are rubbish.

    He was a mathematician.

    And you are not at all educated in this field.

    Wrong.

    "Coun[t]able" is simply another name for potential infinity.

    Not even close.

    You are simply unable to follow reasonable ideas.

    Your "reasonable ideas" are mathematical falsehoods. If your studies and doctorate were in physics, why are you trying (and failing) to get up to
    speed in mathematics? What's in it for you?

    Therefore the sentence "What you (WM) think is reducing isn't
    reducing" exhibits you as a snooty dilettante who cannot distinguish
    between cardinality and reality.

    Hah! He's got to you, has he?

    No, that is my judgement on JB.

    Uninformed opinion, you mean. You're not qualified to make judgments on
    other people's mathematical capabilities.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Sat Mar 22 15:58:51 2025
    Am 22.03.2025 um 15:44 schrieb Moebius:
    Am 22.03.2025 um 15:04 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    It leaves the cardinality unchanged because this notion is tantamount
    to potential infinity.

    You're stuck in the 1880s.

    Nope. Actually, his claim ist absurd nonsense. Es handelt sich bei WM um einen aufmerksamkeitsheischenden, geisteskranker Spinner.

    Hint: (a) Sets have /cardinality/. (b) There are no "potentially
    infinity" sets. Either a set is infinite or not (i.e. finite).

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  • From Moebius@21:1/5 to All on Sat Mar 22 15:44:09 2025
    Am 22.03.2025 um 15:04 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    It leaves the cardinality unchanged because this notion is tantamount
    to potential infinity.

    You're stuck in the 1880s.

    Nope. Actually, his claim ist absurd nonsense. Es handelt sich bei WM um
    einen aufmerksamkeitsheischenden, geisteskranker Spinner.

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  • From Alan Mackenzie@21:1/5 to Moebius on Sat Mar 22 15:28:39 2025
    Moebius <invalid@example.invalid> wrote:
    Am 22.03.2025 um 15:44 schrieb Moebius:
    Am 22.03.2025 um 15:04 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    It leaves the cardinality unchanged because this notion is tantamount
    to potential infinity.

    You're stuck in the 1880s.

    Nope. Actually, his claim ist absurd nonsense. Es handelt sich bei WM um
    einen aufmerksamkeitsheischenden, geisteskranker Spinner.

    Hint: (a) Sets have /cardinality/. (b) There are no "potentially
    infinite" sets. Either a set is infinite or not (i.e. finite).

    Yes, very much so. The term "potentially infinite" has no use in
    mathematics. Philosophers, etc., might cling to it, though.

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Sat Mar 22 21:07:32 2025
    Am 22.03.2025 um 09:34 schrieb Ralf Bader:
    On 03/21/2025 11:15 PM, Moebius wrote:
    Am 21.03.2025 um 22:25 schrieb Alan Mackenzie:

    What was the context of this quote?  Was it a letter to a fellow
    mathematician, or a in a published work, or what?

    I really don't know (can't tell).

    It is from
    4. Mitteilungen zur Lehre vom Transfiniten. VIII Nr. 7/8. 417
    (the header of page 417 in his Gesammelte Abhandlungen)

    Where did you take this quote from?

    IIRC, I've once seen it in one of WM's posts.

    I guess, one of these is the original source:

    Mitteilungen zur Lehre vom Transfiniten. 1. Zeitschrift für Philosophie
    und philosophische Kritik 91 (1887), S. 81 − 125 und 252 − 270.

    Mitteilungen zur Lehre vom Transfiniten. 2. Zeitschrift für Philosophie
    und philosophische Kritik 92 (1888), S. 240 − 265.

    Nuff said (concerning the context). :-P

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  • From Moebius@21:1/5 to All on Sat Mar 22 21:13:05 2025
    Am 22.03.2025 um 21:07 schrieb Moebius:
    Am 22.03.2025 um 09:34 schrieb Ralf Bader:
    On 03/21/2025 11:15 PM, Moebius wrote:
    Am 21.03.2025 um 22:25 schrieb Alan Mackenzie:

    What was the context of this quote?  Was it a letter to a fellow
    mathematician, or a in a published work, or what?

    I really don't know (can't tell).

    It is from
    4. Mitteilungen zur Lehre vom Transfiniten. VIII Nr. 7/8. 417
    (the header of page 417 in his Gesammelte Abhandlungen)

    Where did you take this quote from?

    You can find it here: https://gdz.sub.uni-goettingen.de/id/PPN237853094?tify=%7B%22pages%22%3A%5B429%5D%2C%22pan%22%3A%7B%22x%22%3A0.491%2C%22y%22%3A0.708%7D%2C%22view%22%3A%22info%22%2C%22zoom%22%3A0.454%7D

    IIRC, I've once seen it in one of WM's posts.

    I guess, one of these is the original source:

    Mitteilungen zur Lehre vom Transfiniten. 1. Zeitschrift für Philosophie
    und philosophische Kritik 91 (1887), S. 81 − 125 und 252 − 270.

    Mitteilungen zur Lehre vom Transfiniten. 2. Zeitschrift für Philosophie
    und philosophische Kritik 92 (1888), S. 240 − 265.

    Nuff said (concerning the context). :-P

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  • From Moebius@21:1/5 to All on Sat Mar 22 21:21:55 2025
    Am 22.03.2025 um 21:13 schrieb Moebius:
    Am 22.03.2025 um 21:07 schrieb Moebius:
    Am 22.03.2025 um 09:34 schrieb Ralf Bader:
    On 03/21/2025 11:15 PM, Moebius wrote:
    Am 21.03.2025 um 22:25 schrieb Alan Mackenzie:

    What was the context of this quote?  Was it a letter to a fellow
    mathematician, or a in a published work, or what?

    I really don't know (can't tell).

    It is from
    4. Mitteilungen zur Lehre vom Transfiniten. VIII Nr. 7/8. 417
    (the header of page 417 in his Gesammelte Abhandlungen)

    Where did you take this quote from?

    You can find it here:
    https://gdz.sub.uni-goettingen.de/id/PPN237853094? tify=%7B%22pages%22%3A%5B429%5D%2C%22pan%22%3A%7B%22x%22%3A0.491%2C%22y%22%3A0.708%7D%2C%22view%22%3A%22info%22%2C%22zoom%22%3A0.454%7D

    Zermelo subsumed the "Mitteilungen zur Lehre vom Transfiniten" under the heading "[Cantor's] Abhandlungen zur Geschichte der Mathematik und zur Philosophie".

    Actually, the title of this work is

    GEORG CANTOR
    GESAMMELTE ABHANDLUNGEN
    MATHEMATISCHEN UND PHILOSOPHISCHEN INHALTS
    ...

    IIRC, I've once seen it in one of WM's posts.

    I guess, one of these is the original source:

    Mitteilungen zur Lehre vom Transfiniten. 1. Zeitschrift für
    Philosophie und philosophische Kritik 91 (1887), S. 81 − 125 und
    252 − 270.

    Mitteilungen zur Lehre vom Transfiniten. 2. Zeitschrift für
    Philosophie und philosophische Kritik 92 (1888), S. 240 − 265.

    Nuff said (concerning the context). :-P


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  • From WM@21:1/5 to Alan Mackenzie on Sun Mar 23 18:18:15 2025
    On 22.03.2025 15:04, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16, ....}
    and {1, 3, 5, 7, 9, ....}?

    The second, of course. You need only consider finite sections and take
    the limit. Great mathematicians have devised this method.

    The mathematically correct answer is that they are both the same size (cardinality) because there is a bijection between them.

    Nonsense. The "bijection" is invalid because there are always infinitely
    many elements following after every defined pair.
    I doubt very much Cantor said such rubbish.

    You have pronounced your own sentence: Your opinions are rubbish.

    You should be ashamed to be so misinformed and nevertheless a bigmouth.

    Regards, WM

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  • From Jim Burns@21:1/5 to Ross Finlayson on Sun Mar 23 13:33:37 2025
    On 3/22/2025 9:36 PM, Ross Finlayson wrote:
    On 03/22/2025 01:07 PM, Moebius wrote:

    Nuff said (concerning the context). :-P

    Does it live in
    a mathematical platonist's real universe
    of all the mathematical objects?

    Or rather, mathematical platonism's?

    ⎛ Most writers on the subject seem to agree
    ⎜ that the typical working mathematician is
    ⎜ a Platonist on weekdays and
    ⎜ a formalist on Sundays.

    — Philip J. Davis.

    The typical working mathematician
    can change coats so easily,
    formalist one day and Platonist the next,
    because
    that's a distinction which
    doesn't make a difference to what.they.do.

    One might feel that lack.of.distinction
    is a problem in need of a solution,
    or a beautiful truth, all we need to know.
    Whatever one's attitude towards it,
    it is what it is.

    ⎛ If you try to divine from my posts here
    ⎜ what my own views are concerning these issues,
    ⎜ you will be misled.
    ⎜ Here, I'm engaged in a search for common ground,
    ⎜ without which one can build no higher structure.
    ⎜ What that search looks like, apparently,
    ⎜ is strict formalism.

    ⎜ I approach mathematics from the physical sciences.
    ⎜ I agree with Eugene Wigner on the unreasonableness
    ⎜ of its effectiveness there.

    ⎜ What I tell myself, when I wonder about
    ⎜ the unreasonable effectiveness of mathematics
    ⎜ in the physical sciences,
    ⎜ is that mathematics provides shapes, Jello.molds
    ⎜ into which our physical experiences fit
    ⎜ or do not fit.

    ⎜ Those shapes into which our experiences fit
    ⎜ have theorems attached by imperishable bonds.
    ⎜ These are our physical predictions from theory.
    ⎜ The imperishability of the bonds is merely
    ⎜ mathematics being mathematics.
    ⎜ Mathematics doesn't do 'perishability'.

    ⎜ It seems unreasonable for us to have
    ⎜ what could be called 'knowledge' about
    ⎜ conditions billions of years earlier or later
    ⎜ or billions of light.years away.
    ⎜ I put that down to mathematical argument
    ⎜ which reaches far, far beyond
    ⎜ anything our intuition might have to say,
    ⎜ but, because it's mathematical,
    ⎜ we know is imperishably bonded to this shape
    ⎝ which fits our much less extensive experience.

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  • From WM@21:1/5 to Moebius on Sun Mar 23 20:05:55 2025
    On 22.03.2025 15:58, Moebius wrote:
    Am 22.03.2025 um 15:44 schrieb Moebius:
    Am 22.03.2025 um 15:04 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    It leaves the cardinality unchanged because this notion is tantamount
    to potential infinity.

    You're stuck in the 1880s.

    Nope. Actually, his claim ist absurd nonsense. Es handelt sich bei WM
    um einen aufmerksamkeitsheischenden, geisteskranker Spinner.

    Hint: (a) Sets have /cardinality/. (b) There are no "potentially
    infinity" sets. Either a set is infinite or not (i.e. finite).

    That is a self-contradiction. Cardinality concerns only the potentially infinite subset of an actually infinite set. Bijections of infinite sets
    would have to cover all elements with no remainder.

    Da wir uns aber durch unsre Arbeiten der breiten Heerstraße des
    Transfiniten versichert, sie wohl fundiert und sorgsam gepflastert
    haben, so öffnen wir sie dem Verkehr und stellen sie als eiserne
    Grundlage, nutzbar allen Freunden des potentialen Unendlichen, im
    besonderen aber der wanderlustigen Herbartschen "Grenze" bereitwilligst
    zur Verfügung; gern und ruhig überlassen wir die rastlose der
    Eintönigkeit ihres durchaus nicht beneidenswerten Geschicks; wandle sie
    nur immer weiter, es wird ihr von nun an nie mehr der Boden unter den
    Füßen schwinden. Glück auf die Reise!

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Sun Mar 23 20:22:27 2025
    On 22.03.2025 16:28, Alan Mackenzie wrote:
    The term "potentially infinite" has no use in
    mathematics. Philosophers, etc., might cling to it, though.

    For your education.:

    "On account of the matter I would like to add that in conventional
    mathematics, in particular in differential- and integral calculus, you
    can gain little or no information about the transfinite because here the potential infinite plays the important role, I don't say the only role
    but the role emerging to surface (which most mathematicians are readily satisfied with). Even Leibniz with whom I don't harmonize in many other respects too, has [...] fallen into most spectacular contradictions with respect to the actual infinite." [G. Cantor, letter to A. Schmid (26 Mar
    1887)]

    "Nevertheless the transfinite cannot be considered a subsection of what
    is usually called 'potentially infinite'. Because the latter is not
    (like every individual transfinite and in general everything due to an
    'idea divina') determined in itself, fixed, and unchangeable, but a
    finite in the process of change, having in each of its current states a
    finite size; like, for instance, the temporal duration since the
    beginning of the world, which, when measured in some time-unit, for
    instance a year, is finite in every moment, but always growing beyond
    all finite limits, without ever becoming really infinitely large." [G.
    Cantor, letter to I. Jeiler (13 Oct 1895)]

    "Should we briefly characterize the new view of the infinite introduced
    by Cantor, we could certainly say: In analysis we have to deal only with
    the infinitely small and the infinitely large as a limit-notion, as
    something becoming, emerging, produced, i.e., as we put it, with the
    potential infinite. But this is not the proper infinite. That we have
    for instance when we consider the entirety of the numbers 1, 2, 3, 4,
    ... itself as a completed unit, or the points of a line as an entirety
    of things which is completely available. That sort of infinity is named
    actual infinite." [D. Hilbert: "Über das Unendliche", Mathematische
    Annalen 95 (1925) p. 167]

    "We introduce numbers for counting. This does not at all imply the
    infinity of numbers. For, in what way should we ever arrive at
    infinitely-many countable things? [...] In philosophical terminology we
    say that the infinite of the number sequence is only potential, i.e.,
    existing only as a possibility." [P. Lorenzen: "Das Aktual-Unendliche in
    der Mathematik", Philosophia naturalis 4 (1957) p. 4f]

    "Until then, no one envisioned the possibility that infinities come in different sizes, and moreover, mathematicians had no use for 'actual
    infinity'. The arguments using infinity, including the Differential
    Calculus of Newton and Leibniz, do not require the use of infinite
    sets." [T. Jech: "Set theory", Stanford Encyclopedia of Philosophy (2002)]

    "Numerals constitute a potential infinity. Given any numeral, we can
    construct a new numeral by prefixing it with S. Now imagine this
    potential infinity to be completed. Imagine the inexhaustible process of constructing numerals somehow to have been finished, and call the result
    the set of all numbers, denoted by . Thus  is thought to be an actual infinity or a completed infinity. This is curious terminology, since the etymology of 'infinite' is 'not finished'." [E. Nelson: "Hilbert's
    mistake" (2007) p. 3]

    "A potential infinity is a quantity which is finite but indefinitely
    large. For instance, when we enumerate the natural numbers as 0, 1, 2,
    ..., n, n+1, ..., the enumeration is finite at any point in time, but it
    grows indefinitely and without bound. [...] An actual infinity is a
    completed infinite totality. Examples: , , C[0, 1], L2[0, 1], etc.
    Other examples: gods, devils, etc." [S.G. Simpson: "Potential versus
    actual infinity: Insights from reverse mathematics" (2015)]

    "Potential infinity refers to a procedure that gets closer and closer
    to, but never quite reaches, an infinite end. For instance, the sequence
    of numbers 1, 2, 3, 4, ... gets higher and higher, but it has no end; it
    never gets to infinity. Infinity is just an indication of a direction –
    it's 'somewhere off in the distance'. Chasing this kind of infinity is
    like chasing a rainbow or trying to sail to the edge of the world – you
    may think you see it in the distance, but when you get to where you
    thought it was, you see it is still further away. Geometrically, imagine
    an infinitely long straight line; then 'infinity' is off at the 'end' of
    the line. Analogous procedures are given by limits in calculus, whether
    they use infinity or not. For example, limx0(sinx)/x = 1. This means
    that when we choose values of x that are closer and closer to zero, but
    never quite equal to zero, then (sinx)/x gets closer and closer to one."
    [E. Schechter: "Potential versus completed infinity: Its history and controversy" (5 Dec 2009)]

    Will you show gratitude to be educated in great detail?
    Regards, WM

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  • From Python@21:1/5 to All on Sun Mar 23 19:22:11 2025
    Le 23/03/2025 à 18:18, WM a écrit :
    ..
    You should be ashamed to be so misinformed and nevertheless a bigmouth.


    Crank Wolfgang Mückenheim, if someone should be ashamed it is definitely *you*, not only for your lies and sophistries here and there, but for you
    have abused student at Hochschule Augsburg for years.

    You are worse that the usual crank, you are a disgusting criminal.

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Sun Mar 23 19:39:47 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 16:28, Alan Mackenzie wrote:
    The term "potentially infinite" has no use in
    mathematics. Philosophers, etc., might cling to it, though.

    For your education.:

    "On account of the matter I would like to add that in conventional mathematics, in particular in differential- and integral calculus, you
    can gain little or no information about the transfinite because here the potential infinite plays the important role, I don't say the only role
    but the role emerging to surface (which most mathematicians are readily satisfied with). Even Leibniz with whom I don't harmonize in many other respects too, has [...] fallen into most spectacular contradictions with respect to the actual infinite." [G. Cantor, letter to A. Schmid (26 Mar 1887)]

    [ snip seven more of the same ]

    Will you show gratitude to be educated in great detail?

    What you have cited in no way contradicts what I said above. I repeat, "potentially infinite" has no use in mathematics. You did not, in your voluminous post, cite any indication of a _use_ of "potentially
    infinite", only some philosophising about it.

    In modern mathematics there are the notions finite and infinite. They
    are useful. I challenge you to produce a theorem which cannot be proven
    with those notions, yet can be proven with, additionally, "potentially infinite".

    If neither you nor anybody else can do this, then we must conclude that "potentially infinite" has no use in mathematics.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From WM@21:1/5 to joes on Sun Mar 23 21:52:25 2025
    On 22.03.2025 12:31, joes wrote:

    for infinite sets "reality" and cardinality don't have to correspond.

    So it is! Substance and cardinality have nothing in common because sets
    of very different substance have same cardinality.

    Regards, WM

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  • From Moebius@21:1/5 to All on Sun Mar 23 22:54:35 2025
    Am 23.03.2025 um 22:28 schrieb Alan Mackenzie:

    What is the "reality" (in this sense) of N?

    The "reality" (or rather "substance") of N are its elements

    1, 2, 3, ...

    Clearly, IN\{1} has less "substance" than IN. Actually, the element 1 is missing in IN\{1} (in comparison to IN).

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  • From Moebius@21:1/5 to All on Sun Mar 23 23:07:00 2025
    Am 23.03.2025 um 20:22 schrieb Python:
    Le 23/03/2025 à 18:18, WM a écrit :

    You should be ashamed to be so misinformed and nevertheless a bigmouth.

    WM talking about WM?

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Sun Mar 23 21:28:00 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 12:31, joes wrote:

    for infinite sets "reality" and cardinality don't have to correspond.

    So it is! Substance and cardinality have nothing in common because sets
    of very different substance have same cardinality.

    What is this "reality" or "substance" of which you speak?

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Sun Mar 23 23:10:47 2025
    Am 23.03.2025 um 22:28 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    sets of very different substance [can] have [the] same cardinality.

    Indeed!

    {1, 3, 5, ...} and {2, 4, 6, ...} have "very different substance"
    (actually, NOTHING in common), but still have the same cardinality
    (namely aleph_0).

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  • From Alan Mackenzie@21:1/5 to Moebius on Sun Mar 23 22:19:44 2025
    Moebius <invalid@example.invalid> wrote:
    Am 23.03.2025 um 22:28 schrieb Alan Mackenzie:

    What is the "reality" (in this sense) of N?

    The "reality" (or rather "substance") of N are its elements

    1, 2, 3, ...

    Clearly, IN\{1} has less "substance" than IN. Actually, the element 1 is missing in IN\{1} (in comparison to IN).

    Are you sure? You seem to be implying that the "reality" (or
    "substance") of two sets can't, in general, be compared, unless one is a
    subset of the other. Or something like that.

    WM seemed to be saying that the "reality"/"substance" of any two sets
    could be ranked, with one greater than the other (unless they were,
    somehow, the same).

    I doubt very much that Cantor intended "Realität" to have a mathematical definition. He was merely using the term in an effort to get others to understand how two sets, one a subset of the other, could have the same cardinality.

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Mon Mar 24 01:02:43 2025
    Am 23.03.2025 um 23:19 schrieb Alan Mackenzie:
    Moebius <invalid@example.invalid> wrote:
    Am 23.03.2025 um 22:28 schrieb Alan Mackenzie:

    What is the "reality" (in this sense) of N?

    The "reality" (or rather "substance") of N are its elements

    1, 2, 3, ...

    Clearly, IN\{1} has less "substance" than IN. Actually, the element 1 is
    missing in IN\{1} (in comparison to IN).

    Are you sure?

    Well, I'm just talking. But it seems to me that Cantor thought along
    these lines.

    Clearly, a dead end, of course.

    You seem to be implying that ...

    I'm sorry! I just tried to follow Cantor's thoughts. [Not my way of
    thinking.]

    WM seemed to be saying that the "reality"/"substance" of any two sets
    could be ranked, with one greater than the other

    if on is a subset of the other. :-P

    Ok, let's try to define it:

    A set Y has /more reality/ than a set X if

    X is a PROPER subset of Y.

    I doubt very much that Cantor intended "Realität" to have a mathematical
    definition.

    Agree. But see above.

    He was merely using the term in an effort to get others to
    understand how two sets, one a subset of the other, could have the same cardinality.

    Agree.

    You know, he didn't use that "notion" in his _mathematical_ articles.t"
    to have a mathematical
    definition. He was merely using the term in an effort to get others to understand how two sets, one a subset of the other, could have the same cardinality.


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  • From joes@21:1/5 to All on Mon Mar 24 00:55:20 2025
    Am Sun, 23 Mar 2025 20:05:55 +0100 schrieb WM:
    On 22.03.2025 15:58, Moebius wrote:
    Am 22.03.2025 um 15:44 schrieb Moebius:
    Am 22.03.2025 um 15:04 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    It leaves the cardinality unchanged because this notion is
    tantamount to potential infinity.
    You're stuck in the 1880s.
    Nope. Actually, his claim ist absurd nonsense. Es handelt sich bei WM
    um einen aufmerksamkeitsheischenden, geisteskranker Spinner.
    Hint: (a) Sets have /cardinality/. (b) There are no "potentially
    infinity" sets. Either a set is infinite or not (i.e. finite).
    That is a self-contradiction. Cardinality concerns only the potentially infinite subset of an actually infinite set. Bijections of infinite sets would have to cover all elements with no remainder.
    lolno. An infinite set has a cardinality. Bijections do that. AFAIU,
    "potential infinity" applies only to variables; "actual inf." then
    applies to the result.
    Do all your "pot.inf." sets have an "act.inf." superset? Do "a.i."
    sets without a "p.i." subset exist for you? Can an "a.i." set be
    a subset of a "p.i." one?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Mon Mar 24 01:11:19 2025
    Am Sun, 23 Mar 2025 18:18:15 +0100 schrieb WM:
    On 22.03.2025 15:04, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16,
    ....} and {1, 3, 5, 7, 9, ....}?
    The second, of course. You need only consider finite sections and take
    the limit. Great mathematicians have devised this method.
    They both diverge to exactly omega.

    The mathematically correct answer is that they are both the same size
    (cardinality) because there is a bijection between them.
    Nonsense. The "bijection" is invalid because there are always infinitely
    many elements following after every defined pair.
    Which are also bijected.

    You have pronounced your own sentence: Your opinions are rubbish.
    You should be ashamed to be so misinformed and nevertheless a bigmouth.
    Nothing to add.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From WM@21:1/5 to Alan Mackenzie on Mon Mar 24 20:17:45 2025
    On 23.03.2025 22:28, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 12:31, joes wrote:

    for infinite sets "reality" and cardinality don't have to correspond.

    So it is! Substance and cardinality have nothing in common because sets
    of very different substance have same cardinality.

    What is this "reality" or "substance" of which you speak?

    Substance is by far the better word. It denotes the number of elements.
    The set {1, 2, 3} has more substance than the set {7, 14}. For many sets
    the relative substance cannot be determined. But this drawback is less disastrous than to lump every countable set together.

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    The substance of ℕ is |ℕ|. It is larger than every finite set. The substance of the set of prime numbers is far less than |ℕ| but larger
    than every finite set. These are useful mathematical findings.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Mon Mar 24 20:55:40 2025
    On 23.03.2025 20:39, Alan Mackenzie wrote:
    You did not, in your
    voluminous post, cite any indication of a _use_ of "potentially
    infinite", only some philosophising about it.

    Have you not read Hilbert and Cantor? In analysis potential infinity and
    only it is used.

    In fact all meaningful and correct applications of infinity in
    mathematics concern potential infinity, because actual infinity either
    is a chimera only or it is dark and therefore cannot be manipulated and
    applied in mathematics.

    Regards, WM

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  • From WM@21:1/5 to joes on Mon Mar 24 20:40:07 2025
    On 24.03.2025 02:11, joes wrote:
    Am Sun, 23 Mar 2025 18:18:15 +0100 schrieb WM:

    The "bijection" is invalid because there are always infinitely
    many elements following after every defined pair.
    Which are also bijected.

    How can you prove that?

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Mon Mar 24 21:00:54 2025
    On 23.03.2025 23:19, Alan Mackenzie wrote:

    WM seemed to be saying that the "reality"/"substance" of any two sets
    could be ranked, with one greater than the other (unless they were,
    somehow, the same).

    We should say: Sets with different elements like even and odd integers
    have different substance but same amount of substance (number of elements).

    Regards, WM

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Mon Mar 24 20:12:57 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 20:39, Alan Mackenzie wrote:
    You did not, in your
    voluminous post, cite any indication of a _use_ of "potentially
    infinite", only some philosophising about it.

    Have you not read Hilbert and Cantor? In analysis potential infinity and
    only it is used.

    What is used is the infinite. It needs no redundant qualifier
    "potential".

    You have dishonestly snipped the core of my last post. Here it is
    again:

    In modern mathematics there are the notions finite and infinite. They
    are useful. I challenge you to produce a theorem which cannot be proven
    with those notions, yet can be proven with, additionally, "potentially
    infinite".

    If neither you nor anybody else can do this, then we must conclude that
    "potentially infinite" has no use in mathematics.

    Can I take it that you cannot meet that challenge, and you know of no use
    of "potential infinity" which would justify its existence in the sense of
    my previous two paragraphs?

    In fact all meaningful and correct applications of infinity in
    mathematics concern potential infinity, because actual infinity either
    is a chimera only or it is dark and therefore cannot be manipulated and applied in mathematics.

    "Potential infinity", I repeat, is unnecessary, given the well defined
    notions of "finite" and "infinite". It only introduces confusion.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Mon Mar 24 20:28:39 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 15:04, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16, ....}
    and {1, 3, 5, 7, 9, ....}?

    The second, of course.

    Prove it.

    You need only consider finite sections and take the limit. Great mathematicians have devised this method.

    What on Earth do you mean by "finite sections", if anything? And take
    what limit? Which great mathematician(s) were supposedly involved in
    this method.

    The mathematically correct answer is that they are both the same size
    (cardinality) because there is a bijection between them.

    Nonsense. The "bijection" is invalid because there are always infinitely
    many elements following after every defined pair.

    You are (?deliberately) ignorant of the definition of bijection.
    "Following after every defined pair", if it's not meaningless, is only
    the empty set. The bijection between these two sets exists and is uncontroversial.

    I doubt very much Cantor said such rubbish.

    You have pronounced your own sentence: Your opinions are rubbish.

    You should be ashamed to be so misinformed and nevertheless a bigmouth.

    As I've said more than once, I have a degree in maths. You do not.
    Which one of us is more likely to be misinformed about mathematics?

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Mon Mar 24 20:40:42 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 23:19, Alan Mackenzie wrote:

    WM seemed to be saying that the "reality"/"substance" of any two sets
    could be ranked, with one greater than the other (unless they were,
    somehow, the same).

    We should say: Sets with different elements like even and odd integers
    have different substance but same amount of substance (number of elements).

    Should we? "Substance", in this sense, remains undefined. To say
    things about the "substance" of sets is thus nonsense.

    You've said two sets like the even and odd integers have the "same
    amount of substance"; more nonsense. Then again, there's the set of
    integers divisible by 4, already mentioned. That will also have the
    same "amount of substance" again, presumably.

    Why don't you just use the word cardinality, like everybody else does.
    It is defined mathematically, and generally understood.

    Or can you refute my assertions of nonsense by defining this "substance"/"Realität" in a mathematical fashion?

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Mon Mar 24 21:43:41 2025
    Am 24.03.2025 um 21:12 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Have you not read Hilbert and Cantor? In analysis potential infinity and
    only it is used.

    Mückenheim is referring to an article Hilbert wrote 100 years ago (for a general readership)! [Hilbert, Über das Unendliche, 1925]

    Seems that he -Mückenheim- did not realize the revolution that happened
    in analysis in the past 100 years (due to set theory). <facepalm>

    Actually, this asshole uses standard set theoretic notions in his own "textbook" "für die ersten Semester).

    What is used is the infinite. It needs no redundant qualifier
    "potential".

    Even worse, "potential infinite" actually means _finite_ but capable of arbitrary growth - don't ask!
    "Potential infinity", I repeat, is unnecessary, given the well defined notions of "finite" and "infinite". [...]
    Indeed! Cantor already came to this conclusion...
    .

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  • From Moebius@21:1/5 to All on Mon Mar 24 21:52:40 2025
    Am 24.03.2025 um 21:28 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 15:04, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16, ....} >>> and {1, 3, 5, 7, 9, ....}?

    The second, of course.

    Prove it.

    You need only consider finite sections and take the limit. [...]

    What on Earth do you mean by "finite sections", if anything? And take
    what limit? [...]

    Guess he's referring to this notion: https://en.wikipedia.org/wiki/Natural_density

    .
    .
    .

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Mon Mar 24 20:52:53 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 22:28, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 12:31, joes wrote:

    for infinite sets "reality" and cardinality don't have to correspond.

    So it is! Substance and cardinality have nothing in common because sets
    of very different substance have same cardinality.

    What is this "reality" or "substance" of which you speak?

    Substance is by far the better word. It denotes the number of elements.
    The set {1, 2, 3} has more substance than the set {7, 14}.

    So by "substance" you mean cardinality?

    For many sets the relative substance cannot be determined. But this
    drawback is less disastrous than to lump every countable set together.

    How is it disastrous to "lump every [infinite] countable set together"?
    Does it lead to a mathematical contradiction? It doesn't that I'm aware
    of.

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    The substance of ℕ is |ℕ|. It is larger than every finite set. The substance of the set of prime numbers is far less than |ℕ| ....

    By how much is its "substance" supposedly smaller? Quantify it!

    .... but larger than every finite set. These are useful mathematical findings.

    Are they? What use are they? What mathematical theorems do they enable
    the proof of?

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Mon Mar 24 22:00:39 2025
    Am 24.03.2025 um 21:40 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 23:19, Alan Mackenzie wrote:

    WM seemed to be saying that the "reality"/"substance" of any two sets

    where one is a subset of the other

    could be ranked, with one greater than the other (unless they were,
    somehow, the same).

    We [might] say: Sets with different elements like even and odd integers
    have different substance but same [number of elements].*)

    Indeed! :-P

    With "number of elements" == "cardinality"

    Nuff said. :-P

    __________________________________________________________________________

    *) And what would be the arguments for this claim? I mean, that {2n : n
    e IN} and {2n + 1 : n e IN} have the same "number of elements" in
    WMmath? Just because HE said so?

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  • From Alan Mackenzie@21:1/5 to Moebius on Mon Mar 24 21:06:04 2025
    Moebius <invalid@example.invalid> wrote:
    Am 24.03.2025 um 21:28 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 15:04, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16, ....} >>>> and {1, 3, 5, 7, 9, ....}?

    The second, of course.

    Prove it.

    You need only consider finite sections and take the limit. [...]

    What on Earth do you mean by "finite sections", if anything? And take
    what limit? [...]

    Guess he's referring to this notion: https://en.wikipedia.org/wiki/Natural_density

    OK, thanks. That natural density is not a property of sets, it's a
    property of the natural numbers with additional (arithmetic) structure
    applied to them. The Wikipedia article describes it as a branch of
    number theory, not set theory.

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Mon Mar 24 22:06:54 2025
    Am 24.03.2025 um 22:00 schrieb Moebius:
    Am 24.03.2025 um 21:40 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 23:19, Alan Mackenzie wrote:

    WM seemed to be saying that the "reality"/"substance" of any two sets

    where one is a subset of the other

    could be ranked, with one greater than the other (unless they were,
    somehow, the same).

    We [might] say: Sets with different elements like even and odd integers
    have different substance but same [number of elements].*)

    Indeed! :-P

    With "number of elements" == "cardinality"

    Nuff said. :-P

    __________________________________________________________________________

    *) And what would be the arguments for this claim? I mean, that {2n : n
    e IN} and {2n + 1 : n e IN} have the same "number of elements" in
    WMmath? Just because HE said so?

    See: https://en.wikipedia.org/wiki/Ipse_dixit

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  • From Moebius@21:1/5 to All on Mon Mar 24 22:33:56 2025
    Am 24.03.2025 um 21:12 schrieb Alan Mackenzie:

    You have dishonestly snipped the core of my last post.

    Holy shit! :-)

    Hey, it's Mückenheim!

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  • From WM@21:1/5 to Moebius on Mon Mar 24 22:34:16 2025
    On 24.03.2025 22:26, Moebius wrote:
    IF we measure
    "the size" of a set using the notion of cardinality, clearly "the set of positive integers is not [...] larger than the set of perfect squares". :-)

    That proves that this measure is a triviality but has confused students
    and other authors who think it had a deeper meaning. See the silly
    sentence in Wikipedia: "the set of positive integers is not in fact
    larger than the set of perfect squares". Gelebter Schwachsinn.

    Regards, WM

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  • From Moebius@21:1/5 to All on Mon Mar 24 22:26:34 2025
    Am 24.03.2025 um 22:06 schrieb Alan Mackenzie:
    Moebius <invalid@example.invalid> wrote:

    Guess he's referring to this notion:
    https://en.wikipedia.org/wiki/Natural_density

    OK, thanks. That natural density is not a property of sets [in general]

    Right. But of (certain) subsets of IN.

    See: https://en.wikipedia.org/wiki/Natural_density#Properties_and_examples

    Wikipedia: "... [a] method to measure how "large" a subset of the set of natural numbers is."

    But let's not split hairs here (like Mückenheim).

    ______________________________

    Reading something like this

    "...it may seem intuitively that there are more positive integers than
    perfect squares, because every perfect square is already positive and
    yet many other positive integers exist besides. However, the set of
    positive integers is not in fact larger than the set of perfect squares:
    both sets are infinite and countable and can therefore be put in
    one-to-one correspondence. Nevertheless if one goes through the natural numbers, the squares become increasingly scarce. The notion of natural
    density makes this intuition precise for many, but not all, subsets of
    the naturals (see Schnirelmann density, which is similar to natural
    density but defined for all subsets of IN." (Wikipedia)

    I'd question the claim "However, the set of positive integers is not in
    fact larger than the set of perfect squares" (lol) - here "larger" is interpreted in the sense (context) of /cardinality/. Yeah, IF we measure
    "the size" of a set using the notion of cardinality, clearly "the set of positive integers is not [...] larger than the set of perfect squares". :-)

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  • From Moebius@21:1/5 to All on Mon Mar 24 22:44:21 2025
    Am 24.03.2025 um 22:06 schrieb Alan Mackenzie:

    The Wikipedia article describes [that natural density] it as a branch of number theory, not set theory.

    Sure. But what do you expect from Mückenheim?

    On the other hand... (lol)

    "Die gesamte Mathematik inklusive der klassischen Zahlenbereiche läßt
    sich als Teilgebiet der Mengenlehre auffassen." ["All of mathematics,
    including classical number domains, can be regarded as a sub-field of
    set theory."] (A. Oberschelp, Aufbau des Zahhlensystems, 1968)

    Lit.: https://en.wikipedia.org/wiki/Arnold_Oberschelp

    .
    .
    .

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  • From Moebius@21:1/5 to All on Tue Mar 25 03:10:19 2025
    Am 24.03.2025 um 22:44 schrieb Moebius:

    "Die gesamte Mathematik inklusive der klassischen Zahlenbereiche läßt
    sich als Teilgebiet der Mengenlehre auffassen." ["All of mathematics, including classical number domains, can be regarded as a subfield of
    set theory."] (A. Oberschelp, Aufbau des Zahhlensystems, 1968)

    Too polemic?

    How about: "Die meisten Teile der Mathematik inklusive der klassischen Zahlenbereiche lassen sich als Teilgebiet der Mengenlehre auffassen."
    ["Most parts of mathematics, including classical number domains, can be regarded as a subfield of set theory."]

    :-P

    Lit.: https://en.wikipedia.org/wiki/Arnold_Oberschelp

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  • From Moebius@21:1/5 to All on Tue Mar 25 03:16:12 2025
    Am 25.03.2025 um 03:10 schrieb Moebius:
    Am 24.03.2025 um 22:44 schrieb Moebius:

    "Die gesamte Mathematik inklusive der klassischen Zahlenbereiche läßt
    sich als Teilgebiet der Mengenlehre auffassen." ["All of mathematics,
    including classical number domains, can be regarded as a subfield of
    set theory."] (A. Oberschelp, Aufbau des Zahhlensystems, 1968)

    Too polemic?

    How about: "Die meisten Teile der Mathematik inklusive der klassischen Zahlenbereiche lassen sich als Teilgebiet der Mengenlehre
    auffassen." ["Most parts of mathematics, including classical number
    domains, can be regarded as a subfield of set theory."]

    For example, the "collection" of all groups does not form a set. (!)

    But we can deal with such "collections" (proper classes) in "set
    theories" like NBG and/or MK. So the claim of Oberschelp still holds (at
    least for these cases).

    Lit.: https://en.wikipedia.org/wiki/Arnold_Oberschelp

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  • From Moebius@21:1/5 to All on Tue Mar 25 03:15:37 2025
    Am 25.03.2025 um 03:10 schrieb Moebius:
    Am 24.03.2025 um 22:44 schrieb Moebius:

    "Die gesamte Mathematik inklusive der klassischen Zahlenbereiche läßt
    sich als Teilgebiet der Mengenlehre auffassen." ["All of mathematics,
    including classical number domains, can be regarded as a subfield of
    set theory."] (A. Oberschelp, Aufbau des Zahhlensystems, 1968)

    Too polemic?

    How about: "Die meisten Teile der Mathematik inklusive der klassischen Zahlenbereiche lassen sich als Teilgebiet der Mengenlehre
    auffassen." ["Most parts of mathematics, including classical number
    domains, can be regarded as a subfield of set theory."]

    For example, the "collection" of all groups does not form a set. (!)

    But we can deal with such "collections" (proper classes) in "set
    theories" like NBG and/or MK. So the claim of Oberschelp still holds (at
    least for this cases).

    Lit.: https://en.wikipedia.org/wiki/Arnold_Oberschelp

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  • From joes@21:1/5 to All on Tue Mar 25 08:18:01 2025
    Am Mon, 24 Mar 2025 20:40:07 +0100 schrieb WM:
    On 24.03.2025 02:11, joes wrote:
    Am Sun, 23 Mar 2025 18:18:15 +0100 schrieb WM:

    The "bijection" is invalid because there are always infinitely many
    elements following after every defined pair.
    Which are also bijected.
    How can you prove that?
    How can you disprove it?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Tue Mar 25 08:27:29 2025
    Am Mon, 24 Mar 2025 20:17:45 +0100 schrieb WM:
    On 23.03.2025 22:28, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 12:31, joes wrote:

    for infinite sets "reality" and cardinality don't have to correspond.
    So it is! Substance and cardinality have nothing in common because
    sets of very different substance have same cardinality.
    What is this "reality" or "substance" of which you speak?
    Substance is by far the better word. It denotes the number of elements.
    The set {1, 2, 3} has more substance than the set {7, 14}. For many sets
    the relative substance cannot be determined. But this drawback is less disastrous than to lump every countable set together.
    You can just say subsets.

    The cardinality of N is aleph-0.
    What is the "reality" (in this sense) of N?
    The substance of ℕ is |ℕ|. It is larger than every finite set. The substance of the set of prime numbers is far less than |ℕ| but larger
    than every finite set. These are useful mathematical findings.
    What's the use?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 15:55:37 2025
    On 24.03.2025 22:06, Alan Mackenzie wrote:
    Moebius <invalid@example.invalid> wrote:

    Guess he's referring to this notion:
    https://en.wikipedia.org/wiki/Natural_density

    OK, thanks. That natural density is not a property of sets, it's a
    property of the natural numbers with additional (arithmetic) structure applied to them.

    The natural numbers *are* this arithmetic structure and are the basis of mathematics. If set theory cannot describe it or does not even know it,
    then it is rubbish.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 17:05:00 2025
    On 24.03.2025 21:12, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 20:39, Alan Mackenzie wrote:
    You did not, in your
    voluminous post, cite any indication of a _use_ of "potentially
    infinite", only some philosophising about it.

    Have you not read Hilbert and Cantor? In analysis potential infinity and
    only it is used.

    What is used is the infinite. It needs no redundant qualifier
    "potential".

    You don't grasp it.

    You have dishonestly snipped the core of my last post. Here it is
    again:

    In modern mathematics there are the notions finite and infinite. They
    are useful. I challenge you to produce a theorem which cannot be proven >>> with those notions, yet can be proven with, additionally, "potentially
    infinite".

    I told you that all mathematics is based on potential infinity.

    If neither you nor anybody else can do this, then we must conclude that
    "potentially infinite" has no use in mathematics.

    Actual infinity has no use in any kind of applied mathematics.

    In fact all meaningful and correct applications of infinity in
    mathematics concern potential infinity, because actual infinity either
    is a chimera only or it is dark and therefore cannot be manipulated and
    applied in mathematics.

    "Potential infinity", I repeat, is unnecessary,

    Try to understand the scholars I quoted.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 17:11:23 2025
    On 24.03.2025 21:28, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 22.03.2025 15:04, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Tell me, which of these infinite sets is bigger: {0, 4, 8, 12, 16, ....} >>> and {1, 3, 5, 7, 9, ....}?

    The second, of course.

    Prove it.

    For every large enough interval [0, n] the quotient of number of
    elements is about 2. In the limit 2 is attained.

    You need only consider finite sections and take the limit. Great
    mathematicians have devised this method.

    What on Earth do you mean by "finite sections", if anything?

    Have you never done simple mathematics?

    And take
    what limit? Which great mathematician(s) were supposedly involved in
    this method.

    Try to get better. I will no longer respond to such stupid questions.

    The mathematically correct answer is that they are both the same size
    (cardinality) because there is a bijection between them.

    Nonsense. The "bijection" is invalid because there are always infinitely
    many elements following after every defined pair.

    You are (?deliberately) ignorant of the definition of bijection.
    "Following after every defined pair", if it's not meaningless, is only
    the empty set.

    Try to define a pair that is only followed by the empty set!

    The bijection between these two sets exists and is
    uncontroversial.

    among imbeciles.

    As I've said more than once, I have a degree in maths.

    But you can't understand the simplest problems like that above.

    You do not.

    Wrong.

    Which one of us is more likely to be misinformed about mathematics?

    You show that you can't understand such simple things as the relative magnitudes of the above sets.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 17:13:32 2025
    On 24.03.2025 21:40, Alan Mackenzie wrote:

    Why don't you just use the word cardinality, like everybody else does.

    Cardinality is based on bijections between potentially infinite sets. It
    is a notion of very restricted usefulness.

    It is defined mathematically, and generally understood.

    It is misunderstood.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 16:59:41 2025
    On 24.03.2025 21:52, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    How is it disastrous to "lump every [infinite] countable set together"?
    Does it lead to a mathematical contradiction? It doesn't that I'm aware
    of.

    It doesn't. It is simply a property of potentially infinite initial
    segments of actually infinite set. Disastrous is that some naive minds
    are lead to believe that the actually infinite sets have "in fact" same substance. Assisted imbecility.

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    The substance of ℕ is |ℕ|. It is larger than every finite set. The
    substance of the set of prime numbers is far less than |ℕ| ....

    By how much is its "substance" supposedly smaller? Quantify it!

    It cannot be quantified yet. That would be a rewarding subject of future research.

    .... but larger than every finite set. These are useful mathematical
    findings.

    Are they? What use are they?

    Some researchers may be interested.

    What mathematical theorems do they enable
    the proof of?

    Mathematical theorems can only be proved by use of potential infinity.

    Regards, WM

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Tue Mar 25 16:59:46 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 24.03.2025 21:12, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 23.03.2025 20:39, Alan Mackenzie wrote:
    You did not, in your
    voluminous post, cite any indication of a _use_ of "potentially
    infinite", only some philosophising about it.

    Have you not read Hilbert and Cantor? In analysis potential infinity and >>> only it is used.

    What is used is the infinite. It needs no redundant qualifier
    "potential".

    You don't grasp it.

    I do, very much so. You don't grasp its redundancy. I'm trying to help
    you understand it.

    You have dishonestly snipped the core of my last post. Here it is
    again:

    In modern mathematics there are the notions finite and infinite.
    They are useful. I challenge you to produce a theorem which cannot
    be proven with those notions, yet can be proven with, additionally,
    "potentially infinite".

    I told you that all mathematics is based on potential infinity.

    You were wrong. Unless you can produce that theorem which requires the
    notion of "potentially infinite".

    If neither you nor anybody else can do this, then we must conclude
    that "potentially infinite" has no use in mathematics.

    Actual infinity has no use in any kind of applied mathematics.

    Neither "potential" nor "actual" are necessary qualifications of
    infinite. They just cause confusion. The term infinite stands on its
    own.

    In fact all meaningful and correct applications of infinity in
    mathematics concern potential infinity, because actual infinity
    either is a chimera only or it is dark and therefore cannot be
    manipulated and applied in mathematics.

    "Potential infinity", I repeat, is unnecessary,

    Try to understand the scholars I quoted.

    None of these scholars in your cites were doing mathematics with
    "potential infinity". They were just philosophising. Maybe "potential infinity" has a role to play in philosophy. I wouldn't know. It has no
    role in mathematics.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 17:16:50 2025
    On 24.03.2025 21:40, Alan Mackenzie wrote:

    Or can you refute my assertions of nonsense by defining this "substance"/"Realität" in a mathematical fashion?

    The relative amount of substance of two infinite sets of numbers is the
    limit for n --> oo of the quotient of the numbers of elements within [0, n].

    Regards, WM

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Tue Mar 25 18:03:39 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 24.03.2025 21:40, Alan Mackenzie wrote:

    Or can you refute my assertions of nonsense by defining this
    "substance"/"Realität" in a mathematical fashion?

    The relative amount of substance of two infinite sets of numbers is the limit for n --> oo of the quotient of the numbers of elements within [0, n].

    Thank you!

    So "substance"/"Realität" is not a propery of sets in general, it is a property only of subsets of N.

    So that, for example, it wouldn't apply to the countable sets Q or {1,
    1/2, 1/3, 1/4, ....}.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Tue Mar 25 20:03:11 2025
    Am 25.03.2025 um 19:27 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Just want't to point out this idiotic nonsense:

    [...] It is simply a property of potentially infinite initial
    segments of [an] actually infinite set.

    What the hell are "potentially infinite initial segments of <whatever>".
    Beware of Mückenheim's delusions!

    THIS SILLY ASSHOLE FULL OF SHIT seems to refer to FINITE initial
    segments of <whatever> here. (FISONs in the case of IN.)

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Tue Mar 25 18:27:15 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 24.03.2025 21:52, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    How is it disastrous to "lump every [infinite] countable set together"?
    Does it lead to a mathematical contradiction? It doesn't that I'm aware
    of.

    It doesn't. It is simply a property of potentially infinite initial
    segments of actually infinite set. Disastrous is that some naive minds
    are lead to believe that the actually infinite sets have "in fact" same substance. Assisted imbecility.

    According to one of your other posts today, this "substance" is a
    property only of subsets of N. Other countable sets, or even subsets of
    N not being considered as such, cannot use the concept "substance".

    Countably infinite sets all have the same cardinality.

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    The substance of ℕ is |ℕ|. It is larger than every finite set. The
    substance of the set of prime numbers is far less than |ℕ| ....

    By how much is its "substance" supposedly smaller? Quantify it!

    It cannot be quantified yet. That would be a rewarding subject of future research.

    It can indeed by quantified. The assymptotic distribution of prime
    numbers is known: the probability of a number near n being prime is
    1/log(n). So the proportion of numbers in {1, ..., n} which are prime
    will tend to zero as n tends to infinity.

    .... but larger than every finite set. These are useful mathematical
    findings.

    Are they? What use are they?

    Some researchers may be interested.

    Maybe. On the other hand, maybe not.

    What mathematical theorems do they enable the proof of?

    Mathematical theorems can only be proved by use of potential infinity.

    That's a very bold statement. Many theorems can be proven without regard
    to the infinite. Many others do in fact use the infinite.

    But theorems which require the concept of "potentially infinite", over
    and above plain infinite, for their proof? I've asked you before for an example, and you've yet to come up with one. I don't believe there are
    such theorems, though I'm willing to be persuaded otherwise.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 20:27:26 2025
    On 25.03.2025 19:03, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 24.03.2025 21:40, Alan Mackenzie wrote:

    Or can you refute my assertions of nonsense by defining this
    "substance"/"Realität" in a mathematical fashion?

    The relative amount of substance of two infinite sets of numbers is the
    limit for n --> oo of the quotient of the numbers of elements within [0, n].

    Thank you!

    So "substance"/"Realität" is not a propery of sets in general, it is a property only of subsets of N.

    It has been expanded to rationals and reals the rule of construction and
    the rule of symmetry.

    Regards, WM

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  • From WM@21:1/5 to joes on Tue Mar 25 20:16:10 2025
    On 25.03.2025 09:18, joes wrote:
    Am Mon, 24 Mar 2025 20:40:07 +0100 schrieb WM:
    On 24.03.2025 02:11, joes wrote:
    Am Sun, 23 Mar 2025 18:18:15 +0100 schrieb WM:

    The "bijection" is invalid because there are always infinitely many
    elements following after every defined pair.
    Which are also bijected.
    How can you prove that?
    How can you disprove it?

    Knowing that every pair belongs to a finite initial segment. Upon it
    follow infinitely many elements which cannot be proven to have partners
    in the other set.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Tue Mar 25 21:23:32 2025
    On 25.03.2025 19:27, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 24.03.2025 21:52, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    How is it disastrous to "lump every [infinite] countable set together"?
    Does it lead to a mathematical contradiction? It doesn't that I'm aware >>> of.

    It doesn't. It is simply a property of potentially infinite initial
    segments of actually infinite set. Disastrous is that some naive minds
    are lead to believe that the actually infinite sets have "in fact" same
    substance. Assisted imbecility.

    According to one of your other posts today, this "substance" is a
    property only of subsets of N.

    They supply the simplest explanation. But substance is in every
    non-empty set.

    Countably infinite sets all have the same cardinality.

    That proves that cardinality is rather uninteresting.

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    The substance of ℕ is |ℕ|. It is larger than every finite set. The >>>> substance of the set of prime numbers is far less than |ℕ| ....

    By how much is its "substance" supposedly smaller? Quantify it!

    It cannot be quantified yet. That would be a rewarding subject of future
    research.

    It can indeed by quantified. The assymptotic distribution of prime
    numbers is known: the probability of a number near n being prime is
    1/log(n). So the proportion of numbers in {1, ..., n} which are prime
    will tend to zero as n tends to infinity.

    Tend to yes, but not reaching it.

    .... but larger than every finite set. These are useful mathematical
    findings.

    Are they? What use are they?

    Some researchers may be interested.

    Maybe. On the other hand, maybe not.

    What mathematical theorems do they enable the proof of?

    Mathematical theorems can only be proved by use of potential infinity.

    That's a very bold statement. Many theorems can be proven without regard
    to the infinite.

    Of course I meant theorems using the infinite.

    Many others do in fact use the infinite.

    But theorems which require the concept of "potentially infinite", over
    and above plain infinite, for their proof? I've asked you before for an example, and you've yet to come up with one.

    Every theorem in analysis. This has not much changed since Cantor and
    Hilbert.

    Regards, WM

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  • From Moebius@21:1/5 to All on Tue Mar 25 21:46:45 2025
    Am 25.03.2025 um 20:03 schrieb Moebius:
    Am 25.03.2025 um 19:27 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Just want to point out this idiotic nonsense:

    [...] It is simply a property of potentially infinite initial
    segments of [an] actually infinite set.

    What the hell are "potentially infinite initial segments of <whatever>". Beware of Mückenheim's delusions!

    THIS SILLY ASSHOLE FULL OF SHIT seems to refer to FINITE initial
    segments of <whatever> here. (FISONs in the case of IN.)

    @Mückenhirn: FISONs sind ENDLICHE MENGEN. Also Mengen der "Form" {1, 2,
    3, ..., n} mit n e IN. Davon gibt es _unendlich viele_. Mit anderen
    Worten, die Menge

    FIS := {{1, 2, 3, ..., n} : n e IN}

    ist unendlich. Außerhalb Deines Wahnsystems gilt dann:

    U FIS = IN .

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  • From WM@21:1/5 to Moebius on Tue Mar 25 23:10:26 2025
    On 25.03.2025 21:46, Moebius wrote:

           U FIS = IN .

    Ich ziehe da mathematische Beweise Deiner Behauptung vor.

    The set of FISONs is an inductive set. But it is not ℕ because
    ∀n ∈ UF: |ℕ \ {1, 2, 3, ..., n}| = ℵo.

    The subtraction of the set of all FISONs all of which cannot empty ℕ
    cannot empty ℕ.

    UFIS = ℕ ==> Ø = ℕ

    Regards, WM

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  • From joes@21:1/5 to All on Tue Mar 25 22:20:56 2025
    Am Tue, 25 Mar 2025 20:16:10 +0100 schrieb WM:
    On 25.03.2025 09:18, joes wrote:
    Am Mon, 24 Mar 2025 20:40:07 +0100 schrieb WM:
    On 24.03.2025 02:11, joes wrote:
    Am Sun, 23 Mar 2025 18:18:15 +0100 schrieb WM:

    The "bijection" is invalid because there are always infinitely many
    elements following after every defined pair.
    Which are also bijected.
    How can you prove that?
    How can you disprove it?
    Knowing that every pair belongs to a finite initial segment.
    Of course it does.

    Upon it
    follow infinitely many elements which cannot be proven to have partners
    in the other set.
    Neither can they be disproven.


    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From Moebius@21:1/5 to All on Wed Mar 26 00:53:31 2025
    Am 26.03.2025 um 00:39 schrieb Alan Mackenzie:

    If you have a degree in maths you should be able to say what you mean
    clearly and concisely. Maybe you've lost this skill over the decades
    since your graduation.

    Hint: WM doesn't have a degree in mathematics.

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Tue Mar 25 23:39:49 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 25.03.2025 19:27, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 24.03.2025 21:52, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    How is it disastrous to "lump every [infinite] countable set together"? >>>> Does it lead to a mathematical contradiction? It doesn't that I'm aware >>>> of.

    It doesn't. It is simply a property of potentially infinite initial
    segments of actually infinite set. Disastrous is that some naive minds
    are lead to believe that the actually infinite sets have "in fact" same
    substance. Assisted imbecility.

    According to one of your other posts today, this "substance" is a
    property only of subsets of N.

    They supply the simplest explanation. But substance is in every
    non-empty set.

    Seems doubtful. What you seem to be saying is that every set has a
    superset, you embed the set in that superset, then a portion of the
    superset is the original set. That portion, a number between 0 and 1,
    then becomes the "substance".

    You're saying that the "substance" isn't a property of a set as such,
    it's a property of a relationship between a superset and a subset.

    For example, to get the "substance" of N with respect to Q, you could embed
    it in the superset Q: You'd get something like: {0, 1, 1/2, 2, 1/3, 3,
    1/4, 2/3, 3/2, 4, 1/5, 5, ....}. Then this "substance" would come out as
    zero.

    So, to come back to my original example, the "substance" of {0, 4, 8, 12,
    16, ...} wrt N is 1/4. The substance of {1, 3, 5, 7, 9, ...} wrt {0,
    1/2, 1, 3/2, 2, 5/2, 3, ....} is also 1/4. Their "subtances" are thus
    the same. Or could be made the same. Or the notion of "substance" in
    ill thought out and undefined.

    I haven't come across this notion of "substance"/"Realität" before, and
    it doesn't feel like solid maths. It all feels as though you are making
    it up as you go along.

    Countably infinite sets all have the same cardinality.

    That proves that cardinality is rather uninteresting.

    On the contrary, it is fascinating.

    The cardinality of N is aleph-0.

    What is the "reality" (in this sense) of N?

    The substance of ℕ is |ℕ|. It is larger than every finite set. The >>>>> substance of the set of prime numbers is far less than |ℕ| ....

    By how much is its "substance" supposedly smaller? Quantify it!

    It cannot be quantified yet. That would be a rewarding subject of future >>> research.

    It can indeed by quantified. The assymptotic distribution of prime
    numbers is known: the probability of a number near n being prime is
    1/log(n). So the proportion of numbers in {1, ..., n} which are prime
    will tend to zero as n tends to infinity.

    Tend to yes, but not reaching it.

    I thought you just said you had a degree in maths. But you don't seem to understand the process of limits (a bit like John Gabriel didn't when he
    was still around). Those two things appear to contradict eachother.

    .... but larger than every finite set. These are useful mathematical >>>>> findings.

    Are they? What use are they?

    Some researchers may be interested.

    Maybe. On the other hand, maybe not.

    What mathematical theorems do they enable the proof of?

    Mathematical theorems can only be proved by use of potential infinity.

    That's a very bold statement. Many theorems can be proven without regard
    to the infinite.

    Of course I meant theorems using the infinite.

    If you have a degree in maths you should be able to say what you mean
    clearly and concisely. Maybe you've lost this skill over the decades
    since your graduation.

    Many others do in fact use the infinite.

    But theorems which require the concept of "potentially infinite", over
    and above plain infinite, for their proof? I've asked you before for an
    example, and you've yet to come up with one.

    Every theorem in analysis. This has not much changed since Cantor and Hilbert.

    Theroems in analysis require the infinite yes. They don't require the confusing notion of "potentially infinite". In my undergraduate studies,
    the term "potentially infinite" wasn't used a single time. The first
    time I came across it was in this newsgroup just a few years ago.

    Or again thinking back to John Gabriel, he had his own non-standard
    vocabulary, where he would use "number" to mean what everybody else
    called rational number, and "incomensurate magnitude" to mean irrational number. It didn't get him anywhere.

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite". That won't get you anywhere either.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Wed Mar 26 01:06:42 2025
    Am 26.03.2025 um 00:39 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    What everybody else refers to as infinte, you seem to want to call "potentially infinite".

    Actually, it's rather the other way round. WM has a tendency to call
    things "potentially infinite" which everyone else would call "finite".

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  • From Moebius@21:1/5 to All on Wed Mar 26 01:14:18 2025
    Am 26.03.2025 um 01:06 schrieb Moebius:
    Am 26.03.2025 um 00:39 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".

    Actually, it's rather the other way round. WM has a tendency to call
    things "potentially infinite" which everyone else would call "finite".

    It seems that he recently recognised this himself, leading to the absurd
    phrase

    potentially (in-)finite <so-and-so> (WM)

    <facepalm>

    (You won't find such a the notion ANYWHERE ... else.)

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  • From Moebius@21:1/5 to All on Wed Mar 26 01:53:01 2025
    Am 26.03.2025 um 01:44 schrieb Moebius:
    Am 26.03.2025 um 01:14 schrieb Moebius:
    Am 26.03.2025 um 01:06 schrieb Moebius:
    Am 26.03.2025 um 00:39 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".

    Actually, it's rather the other way round. WM has a tendency to call
    things "potentially infinite" which everyone else would call "finite".

    It seems that he recently recognised this himself, leading to the absurd
    phrase

                        potentially (in-)finite <so-and-so>  (WM)

    <facepalm>

    (You won't find such a the notion ANYWHERE ... else.)

    "The amount of energy needed to refute bullshit is an order of magnitude bigger than that needed to produce it." (Brandolini's law, bullshit
    asymmetry principle)

    "In 1845, Frédéric Bastiat expressed an early notion of the law:

    We must confess that our adversaries have a marked advantage over us in
    the discussion. In very few words they can announce a half-truth; and in
    order to demonstrate that it is incomplete [or nonsense --moebius], we
    are obliged to have recourse to long and dry dissertations.

    — Economic Sophisms, First Series (1845)

    Prior to Brandolini's definition, Italian blogger Uriel Fanelli and
    researcher Jonathan Koomey, creator of Koomey's law, also shared
    thoughts aligning with the bullshit asymmetry principle. Fanelli stated:

    "An idiot can create more bullshit than you could ever hope to refute",

    when generally translated in Calling Bullshit: The Art of Skepticism in
    a Data-Driven World."

    .
    .
    .

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  • From Moebius@21:1/5 to All on Wed Mar 26 01:44:38 2025
    Am 26.03.2025 um 01:14 schrieb Moebius:
    Am 26.03.2025 um 01:06 schrieb Moebius:
    Am 26.03.2025 um 00:39 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".

    Actually, it's rather the other way round. WM has a tendency to call
    things "potentially infinite" which everyone else would call "finite".

    It seems that he recently recognised this himself, leading to the absurd phrase

                       potentially (in-)finite <so-and-so>  (WM)

    <facepalm>

    (You won't find such a the notion ANYWHERE ... else.)

    "The amount of energy needed to refute bullshit is an order of magnitude
    bigger than that needed to produce it." (Brandolini's law, bullshit
    asymmetry principle)

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  • From WM@21:1/5 to joes on Wed Mar 26 17:30:21 2025
    On 25.03.2025 23:20, joes wrote:
    Am Tue, 25 Mar 2025 20:16:10 +0100 schrieb WM:
    On 25.03.2025 09:18, joes wrote:
    Am Mon, 24 Mar 2025 20:40:07 +0100 schrieb WM:
    On 24.03.2025 02:11, joes wrote:
    Am Sun, 23 Mar 2025 18:18:15 +0100 schrieb WM:

    The "bijection" is invalid because there are always infinitely many >>>>>> elements following after every defined pair.
    Which are also bijected.
    How can you prove that?
    How can you disprove it?
    Knowing that every pair belongs to a finite initial segment.
    Of course it does.

    Upon it
    follow infinitely many elements which cannot be proven to have partners
    in the other set.
    Neither can they be disproven.

    Disproven is it for instance by the following:

    X-O-Matrices

    All positive fractions

    1/1, 1/2, 1/3, 1/4, ...
    2/1, 2/2, 2/3, 2/4, ...
    3/1, 3/2, 3/3, 3/4, ...
    4/1, 4/2, 4/3, 4/4, ...
    ...

    can be indexed by the Cantor function k = (m + n - 1)(m + n - 2)/2 + m
    which attaches the index k to the fraction m/n in Cantor's sequence

    1/1, 1/2, 2/1, 1/3, 2/2, 3/1, 1/4, 2/3, 3/2, 4/1, 1/5, 2/4, 3/3, 4/2, 5/1, 1/6, 2/5, 3/4, ... .

    Its terms can be represented by matrices. When we attach all indeXes k =
    1, 2, 3, ..., for clarity represented by X, to the integer fractions m/1
    and indicate missing indexes by hOles O, then we get the matrix M(0) as starting position:

    XOOO... XXOO... XXOO... XXXO... ... XXXX...
    XOOO... OOOO... XOOO... XOOO... ... XXXX...
    XOOO... XOOO... OOOO... OOOO... ... XXXX...
    XOOO... XOOO... XOOO... OOOO... ... XXXX...
    ... ... ... ... ...
    M(0) M(2) M(3) M(4) M(∞)

    M(1) is the same as M(0) because index 1 remains at 1/1. In M(2) index 2
    from 2/1 has been attached to 1/2. In M(3) index 3 from 3/1 has been
    attached to 2/1. In M(4) index 4 from 4/1 has been attached to 1/3. Successively all fractions of the sequence get indexed. In the limit,
    denoted by M(∞), we see no fraction without index remaining. Note that
    the only difference to Cantor's enumeration is that Cantor does not
    render account for the source of the indices.

    Every X, representing the index k, when taken from its present fraction
    m/n, is replaced by the O taken from the fraction to be indexed by this
    k. Its last carrier m/n will be indexed later by another index.
    Important is that, when continuing, no O can leave the matrix as long as
    any index X blocks the only possible drain, i.e., the first column. And
    if leaving, where should it settle?

    As long as indexes are in the drain, no O has left. The presence of all
    O indicates that almost all fractions are not indexed. And after all
    indexes have been issued and the drain has become free, no indexes are available which could index the remaining matrix elements, yet covered by O.

    It should go without saying that by rearranging the X of M(0) never a
    complete covering can be realized. Lossless transpositions cannot suffer losses. The limit matrix M(∞) only shows what should have happened when
    all fractions were indexed. Logic proves that this cannot have happened
    by exchanges. The only explanation for finally seeing M(∞) is that there
    are invisible matrix positions, existing already at the start. Obviously
    by exchanging O and X no O can leave the matrix, but the O can disappear
    by moving without end, from visible to invisible positions.

    Regards, WM



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  • From WM@21:1/5 to Moebius on Wed Mar 26 17:36:30 2025
    On 26.03.2025 01:14, Moebius wrote:
    Am 26.03.2025 um 01:06 schrieb Moebius:
    Am 26.03.2025 um 00:39 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".

    Actually, it's rather the other way round. WM has a tendency to call
    things "potentially infinite" which everyone else would call "finite".

    It seems that he recently recognised this himself, leading to the absurd phrase

                       potentially (in-)finite <so-and-so>  (WM)

    No! The correct phrase is (potentially in-)finite.
    (You won't find such a the notion ANYWHERE ... else.)

    yet.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Wed Mar 26 20:36:40 2025
    On 26.03.2025 00:39, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    substance is in every non-empty set.

    Seems doubtful. What you seem to be saying is that every set has a
    superset, you embed the set in that superset, then a portion of the
    superset is the original set. That portion, a number between 0 and 1,
    then becomes the "substance".

    No, that is not what I meant. Substance is simply the elements of the
    set. The amount of substance is the number of elements. This number
    exists also for actually infinity sets but cannot be expressed by
    natural numbers.

    We only know that ∀k,n ∈ ℕ_def: |ℕ|/k > n.

    You're saying that the "substance" isn't a property of a set as such,
    it's a property of a relationship between a superset and a subset.

    The relative amount of substance can be determined. The set {1, 2, 3}
    has more substance than the set {father, mother}.

    For example, to get the "substance" of N with respect to Q, you could embed it in the superset Q: You'd get something like: {0, 1, 1/2, 2, 1/3, 3,
    1/4, 2/3, 3/2, 4, 1/5, 5, ....}. Then this "substance" would come out as zero.

    Nearly. It is smaller than any definable fraction.

    So, to come back to my original example, the "substance" of {0, 4, 8, 12,
    16, ...} wrt N is 1/4.

    Yes.

    The substance of {1, 3, 5, 7, 9, ...} wrt {0,
    1/2, 1, 3/2, 2, 5/2, 3, ....} is also 1/4.

    Yes.

    Their "subtances" are thus
    the same.

    Yes. Their amounts of substance, to be precise.

    I haven't come across this notion of "substance"/"Realität" before, and
    it doesn't feel like solid maths. It all feels as though you are making
    it up as you go along.

    Reality is Cantor's expression, Substance is Fritsche's (better)
    expression. For all finite sets, it is solid maths. Limits are
    well-known from analysis.

    Countably infinite sets all have the same cardinality.

    That proves that cardinality is rather uninteresting.

    On the contrary, it is fascinating.

    If you consider it with cool blood, then you will recognize that all
    pairs of a bijection with ℕ are defined within a finite initial segment
    [0, n]. That is true for every n. But the infinity lies in the
    successors which are undefined.

    Tend to yes, but not reaching it.

    I thought you just said you had a degree in maths. But you don't seem to understand the process of limits (a bit like John Gabriel didn't when he
    was still around).

    0/oo = 0. 1/oo is smaller than every definable fraction.
    Every theorem in analysis. This has not much changed since Cantor and
    Hilbert.

    Theroems in analysis require the infinite yes. They don't require the confusing notion of "potentially infinite".

    They have been created using only this notion. And also Cantor's
    "bijections" bare based upon potential infinity.

    In my undergraduate studies,
    the term "potentially infinite" wasn't used a single time. The first
    time I came across it was in this newsgroup just a few years ago.

    The Bourbakis have tried to exorcize the potential infinite from
    mathematics. Your teachers have been taught by them or their pupils.

    What everybody else refers to as infinte, you seem to want to call "potentially infinite".

    The potential infinite is a variable finite. Cantor's actual infinity is
    not variable but fixed. (Therefore Hilbert's hotel is potential infinity.)

    Regards, WM


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  • From joes@21:1/5 to All on Wed Mar 26 20:06:24 2025
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:
    On 26.03.2025 00:39, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    substance is in every non-empty set.
    Seems doubtful. What you seem to be saying is that every set has a
    superset, you embed the set in that superset, then a portion of the
    superset is the original set. That portion, a number between 0 and 1,
    then becomes the "substance".
    No, that is not what I meant. Substance is simply the elements of the
    set. The amount of substance is the number of elements. This number
    exists also for actually infinity sets but cannot be expressed by
    natural numbers.
    We only know that ∀k,n ∈ ℕ_def: |ℕ|/k > n.
    That makes all of them >=omega.

    You're saying that the "substance" isn't a property of a set as such,
    it's a property of a relationship between a superset and a subset.
    The relative amount of substance can be determined. The set {1, 2, 3}
    has more substance than the set {father, mother}.
    Try it with infinite sets.

    For example, to get the "substance" of N with respect to Q, you could
    embed it in the superset Q: You'd get something like: {0, 1, 1/2, 2,
    1/3, 3, 1/4, 2/3, 3/2, 4, 1/5, 5, ....}. Then this "substance" would
    come out as zero.
    Nearly. It is smaller than any definable fraction.
    Infinitely so!

    So, to come back to my original example, the "substance" of {0, 4, 8,
    12, 16, ...} wrt N is 1/4.
    Yes.
    The substance of {1, 3, 5, 7, 9, ...} wrt {0,
    1/2, 1, 3/2, 2, 5/2, 3, ....} is also 1/4.
    Yes.
    Their "subtances" are thus the same.
    Yes. Their amounts of substance, to be precise.

    I haven't come across this notion of "substance"/"Realität" before, and
    it doesn't feel like solid maths. It all feels as though you are
    making it up as you go along.
    Reality is Cantor's expression, Substance is Fritsche's (better)
    expression. For all finite sets, it is solid maths. Limits are
    well-known from analysis.
    Except to you. For finite sets you can just use cardinality.

    Countably infinite sets all have the same cardinality.
    That proves that cardinality is rather uninteresting.
    On the contrary, it is fascinating.
    If you consider it with cool blood, then you will recognize that all
    pairs of a bijection with ℕ are defined within a finite initial segment
    [0, n]. That is true for every n. But the infinity lies in the
    successors which are undefined.
    Yes, every natural number has a FIS. "Undefined numbers" aren't naturals.

    Tend to yes, but not reaching it.
    I thought you just said you had a degree in maths.
    No, I asked him for the title.

    But you don't seem
    to understand the process of limits (a bit like John Gabriel didn't
    when he was still around).
    0/oo = 0. 1/oo is smaller than every definable fraction.
    There is no real number other than 0.

    Every theorem in analysis. This has not much changed since Cantor and
    Hilbert.
    Theroems in analysis require the infinite yes. They don't require the
    confusing notion of "potentially infinite".
    They have been created using only this notion. And also Cantor's
    "bijections" are based upon potential infinity.
    Yes, nobody refers to "actual infinity".

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".
    The potential infinite is a variable finite. Cantor's actual infinity is
    not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From WM@21:1/5 to joes on Wed Mar 26 21:28:52 2025
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity is
    not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.

    The number of guests/rooms in Hilbert's hotel is infinite but can grow.
    That is variable infinity.

    Regards, WM

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Wed Mar 26 21:38:25 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity is >>> not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.

    The number of guests/rooms in Hilbert's hotel is infinite but can grow.
    That is variable infinity.

    You are mistaken. (Countable) infinity stays the same when you add
    finite and countably infinite numbers to it. Thus in Hilbert's hotel,
    although all the rooms are occupied, one of these rooms can be vacated
    to make room for a new guest without expelling an existing guest.

    Adding that new guest doesn't change the number of guests in the hotel,
    or the number of rooms required. See many of Jim's posts over the last
    few days for details.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Wed Mar 26 23:18:07 2025
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity is >>>> not variable but fixed. (Therefore Hilbert's hotel [concerns]

    "actual infinity".

    The number of [...] rooms in Hilbert's hotel is infinite but [...] grow[s].

    No, it doesn't.

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Thu Mar 27 11:18:27 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 00:39, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    substance is in every non-empty set.

    Seems doubtful. What you seem to be saying is that every set has a
    superset, you embed the set in that superset, then a portion of the
    superset is the original set. That portion, a number between 0 and 1,
    then becomes the "substance".

    No, that is not what I meant. Substance is simply the elements of the
    set. The amount of substance is the number of elements.

    You seem to mean the cardinality of the set.

    This number exists also for actually infinite sets but cannot be
    expressed by natural numbers.

    We only know that ∀k,n ∈ ℕ_def: |ℕ|/k > n.

    |N|/k is undefined.

    You're saying that the "substance" isn't a property of a set as such,
    it's a property of a relationship between a superset and a subset.

    The relative amount of substance can be determined. The set {1, 2, 3}
    has more substance than the set {father, mother}.

    You mean it has a larger cardinality.

    For example, to get the "substance" of N with respect to Q, you could
    embed it in the superset Q: You'd get something like: {0, 1, 1/2, 2,
    1/3, 3, 1/4, 2/3, 3/2, 4, 1/5, 5, ....}. Then this "substance" would
    come out as zero.

    Nearly. It is smaller than any definable fraction.

    Crank talk. You don't understand limits, as I've already said. Have you really got a degree in mathematics? It seems unlikely.

    So, to come back to my original example, the "substance" of {0, 4, 8,
    12, 16, ...} wrt N is 1/4.

    Yes.

    The substance of {1, 3, 5, 7, 9, ...} wrt {0, 1/2, 1, 3/2, 2, 5/2, 3,
    ....} is also 1/4.

    Yes.

    Their "subtances" are thus the same.

    Yes. Their amounts of substance, to be precise.

    Or their cardinality, to be even more precise.

    I haven't come across this notion of "substance"/"Realität" before,
    and it doesn't feel like solid maths. It all feels as though you are
    making it up as you go along.

    Reality is Cantor's expression, Substance is Fritsche's (better)
    expression. For all finite sets, it is solid maths. Limits are
    well-known from analysis.

    Countably infinite sets all have the same cardinality.

    That proves that cardinality is rather uninteresting.

    On the contrary, it is fascinating.

    If you consider it with cool blood, then you will recognize that all
    pairs of a bijection with ℕ are defined within a finite initial segment [0, n]. That is true for every n. But the infinity lies in the
    successors which are undefined.

    That's pure baloney. Every element of a bijection is an ordered pair of
    an element of set 1 and an element of set 2. Each element of these sets
    occurs in exactly one ordered pair. There is no need to obfuscate this definition with considerations of finite initial segments or infinity or
    what have you.

    Tend to yes, but not reaching it.

    I thought you just said you had a degree in maths. But you don't seem to
    understand the process of limits (a bit like John Gabriel didn't when he
    was still around).

    0/oo = 0. 1/oo is smaller than every definable fraction.

    More crank talk. Ordinary arithmetic is not defined on infinity. And
    "smaller than every definable fraction" is zero.

    Every theorem in analysis. This has not much changed since Cantor and
    Hilbert.

    Theroems in analysis require the infinite yes. They don't require the
    confusing notion of "potentially infinite".

    They have been created using only this notion. And also Cantor's "bijections" bare based upon potential infinity.

    But there is no theorem requiring "potentially infinite" for its proof that isn't equally valid using the simpler notion of "infinite". "Potentially infinite" is a needless complication, if it's even well defined.

    In my undergraduate studies, the term "potentially infinite" wasn't
    used a single time. The first time I came across it was in this
    newsgroup just a few years ago.

    The Bourbakis have tried to exorcize the potential infinite from mathematics. Your teachers have been taught by them or their pupils.

    "Potentially infinite" doesn't belong in mathematics. It's not of any
    use, and causes only obfuscation and confusion, not illumination.

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".

    The potential infinite is a variable finite. Cantor's actual infinity
    is not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)

    Hilbert's hotel is infinite, not "variably finite".

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From joes@21:1/5 to All on Thu Mar 27 14:59:53 2025
    Am Wed, 26 Mar 2025 21:28:52 +0100 schrieb WM:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity
    is not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.
    The number of guests/rooms in Hilbert's hotel is infinite but can grow.
    That is variable infinity.
    The number of rooms is fixed, otherwise it weren't interesting.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From Moebius@21:1/5 to All on Thu Mar 27 17:45:23 2025
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Crank talk. You don't understand limits, as I've already said. Have you really got a degree in mathematics? It seems unlikely.

    WM doesn't have a degree in mathematics.

    Cantor's "bijections" bare based upon potential infinity.

    Complete nonsense.

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  • From Alan Mackenzie@21:1/5 to Moebius on Thu Mar 27 17:50:46 2025
    Moebius <invalid@example.invalid> wrote:
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Crank talk. You don't understand limits, as I've already said. Have you
    really got a degree in mathematics? It seems unlikely.

    WM doesn't have a degree in mathematics.

    He denied not having one. Most of the time, people don't outright lie
    on Usenet. They twist and turn, answering direct questiongs evasively
    and inadequately, and assert half truths.

    My working theory at the moment is that WM has some university degree
    which had a small component of mathematics, but that part of his degree
    didn't cover rigorous analysis or rigorous set theory, or anything much
    else rigorous. His outpourings on this newsgroup (as well as on its
    German counterpart) pretty much rule out systematic study of the
    foundations of mathematics.

    Maybe WM would like to clarify exactly what his university degree
    consisted of.

    Cantor's "bijections" are based upon potential infinity.

    Complete nonsense.

    Indeed.

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From WM@21:1/5 to All on Thu Mar 27 20:31:16 2025
    Am 27.03.2025 um 15:59 schrieb joes:
    Am Wed, 26 Mar 2025 21:28:52 +0100 schrieb WM:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity
    is not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.
    The number of guests/rooms in Hilbert's hotel is infinite but can grow.
    That is variable infinity.
    The number of rooms is fixed,

    One more guest requires one more room.

    otherwise it weren't interesting.

    It is interestimng only insofar as it shows that adherents of set theory
    are ready to believe every shit.

    Regards, WM

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  • From WM@21:1/5 to All on Thu Mar 27 21:11:00 2025
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:


    The number of [...] rooms in Hilbert's hotel is infinite but [...]
    grow[s].

    No, it doesn't.

    And the number of guests?

    Real fools like really counterintuitive "results".

    Regards, WM

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  • From WM@21:1/5 to All on Thu Mar 27 21:07:18 2025
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Substance is simply the elements of the
    set. The amount of substance is the number of elements.

    You seem to mean the cardinality of the set.

    Not at all! Cardinality concerns only definable elements.

    This number exists also for actually infinite sets but cannot be
    expressed by natural numbers.

    We only know that ∀k,n ∈ ℕ_def: |ℕ|/k > n.

    |N|/k is undefined.

    It is undefined *as a finite number*. But it is defined by
    |N|/(k-1) > |N|/k > |N|/(k+1).

    You're saying that the "substance" isn't a property of a set as such,
    it's a property of a relationship between a superset and a subset.

    The relative amount of substance can be determined. The set {1, 2, 3}
    has more substance than the set {father, mother}.

    You mean it has a larger cardinality.

    For finite sets cardinality is a meaningful notion expressing the number
    of elements. But I dislike it because it is often extended to cover
    infinite sets where it does not describe the number of elements.

    For example, to get the "substance" of N with respect to Q, you could
    embed it in the superset Q: You'd get something like: {0, 1, 1/2, 2,
    1/3, 3, 1/4, 2/3, 3/2, 4, 1/5, 5, ....}. Then this "substance" would
    come out as zero.

    Nearly. It is smaller than any definable fraction.

    Crank talk.

    Ideas surpassing your knowledge by far.

    So, to come back to my original example, the "substance" of {0, 4, 8,
    12, 16, ...} wrt N is 1/4.

    Yes.

    The substance of {1, 3, 5, 7, 9, ...} wrt {0, 1/2, 1, 3/2, 2, 5/2, 3,
    ....} is also 1/4.

    Yes.

    Their "subtances" are thus the same.

    Yes. Their amounts of substance, to be precise.

    Or their cardinality, to be even more precise.

    No, to be imprecise. Their numbers of elements differ but their
    cardinality is the same.

    If you consider it with cool blood, then you will recognize that all
    pairs of a bijection with ℕ are defined within a finite initial segment
    [0, n]. That is true for every n. But the infinity lies in the
    successors which are undefined.

    That's pure baloney. Every element of a bijection is an ordered pair of
    an element of set 1 and an element of set 2. Each element of these sets occurs in exactly one ordered pair. There is no need to obfuscate this definition with considerations of finite initial segments or infinity or
    what have you.

    It is correct and shows that cardinality is nonsense.

    Tend to yes, but not reaching it.

    I thought you just said you had a degree in maths. But you don't seem to >>> understand the process of limits (a bit like John Gabriel didn't when he >>> was still around).

    0/oo = 0. 1/oo is smaller than every definable fraction.

    More crank talk. Ordinary arithmetic is not defined on infinity. And "smaller than every definable fraction" is zero.

    Study surreal and hyperreal numbers which appear even in modern mathematics.

    The Bourbakis have tried to exorcize the potential infinite from
    mathematics. Your teachers have been taught by them or their pupils.

    "Potentially infinite" doesn't belong in mathematics. It's not of any
    use, and causes only obfuscation and confusion, not illumination.

    Look, you don't know much. Not even surreal and hyperreal numbers. Why
    should I take your word on other topics as fact?>
    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".

    The potential infinite is a variable finite. Cantor's actual infinity
    is not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)

    Hilbert's hotel is infinite, not "variably finite".

    Then its number of guests and of rooms could not change.

    Regards, WM

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  • From WM@21:1/5 to All on Thu Mar 27 21:15:39 2025
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity is >>>> not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.

    The number of guests/rooms in Hilbert's hotel is infinite but can grow.
    That is variable infinity.

    You are mistaken. (Countable) infinity stays the same when you add
    finite and countably infinite numbers to it.

    That proves that cardinality is nonsense. When a new guest arrives, then
    the number of guests grows by 1.

    Thus in Hilbert's hotel,
    although all the rooms are occupied, one of these rooms can be vacated
    to make room for a new guest without expelling an existing guest.

    Real fools are really delighted by counterintuitive results.

    Adding that new guest doesn't change the number of guests in the hotel,
    or the number of rooms required.

    Real fools are really delighted by counterintuitive results.

    See many of Jim's posts over the last
    few days for details.

    There is only one important detail, namely that lossless exchanges cause losses. It is sufficient to reject every intelligent being.

    REgards, WM

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  • From Jim Burns@21:1/5 to Alan Mackenzie on Thu Mar 27 17:01:30 2025
    On 3/27/2025 1:50 PM, Alan Mackenzie wrote:
    Moebius <invalid@example.invalid> wrote:
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:



    Crank talk.
    You don't understand limits, as I've already said.
    Have you really got a degree in mathematics?
    It seems unlikely.

    WM doesn't have a degree in mathematics.

    He denied not having one.
    Most of the time,

    Hmmm.

    Most of the time,
    people don't outright lie on Usenet.
    They twist and turn,
    answering direct questiongs evasively and inadequately,
    and assert half truths.

    My working theory at the moment is that
    WM has some university degree which had
    a small component of mathematics, but
    that part of his degree didn't cover
    rigorous analysis or rigorous set theory,
    or anything much else rigorous.

    https://de.wikipedia.org/wiki/Wolfgang_M%C3%BCckenheim
    [Google->Eng]
    ⎛ From 1973 to 1977, Mückenheim studied physics with
    ⎜ minors in mathematics, astronomy and chemistry ...

    ⎜ In 1979, he obtained his doctorate in physics with
    ⎜ a dissertation on elastic photon scattering on
    ⎝ the ¹²²uranium, ...

    ⎛ For the record, my (JB's) own formal education ends with
    ⎜ a bachelor's degree in physics and
    ⎝ minors in mathematics and computer science.

    For what it's worth,
    on paper, Mückenheim is more qualified than I am.
    I suspect that that irks him to no end.

    His outpourings on this newsgroup
    (as well as on its German counterpart)
    pretty much rule out systematic study of
    the foundations of mathematics.

    I am honestly mystified by
    what I need to explain to Mückenheim,
    someone who apparently has taken
    upper.level courses in mathematics.

    Am I unusual in having had to prove things
    in such courses, for homework and for tests?

    But I have a theory.

    There once was a poster of the crankish persuasion,
    convinced that he was going to prove
    Fermat's Last Theorem at a highschool level of difficulty.
    He seemed to know very little mathematics.

    I had some reason to look back over
    his much.earlier posts, and
    I was surprised to find that
    that, much _earlier_ he apparently knew _more_
    than the same (?) poster later, _after_ years of
    arguing mathematics with mathematicians.

    My theory is that
    trying to defend bullshit rots the brain.

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  • From joes@21:1/5 to All on Thu Mar 27 21:31:36 2025
    Am Thu, 27 Mar 2025 20:31:16 +0100 schrieb WM:
    Am 27.03.2025 um 15:59 schrieb joes:
    Am Wed, 26 Mar 2025 21:28:52 +0100 schrieb WM:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual
    infinity is not variable but fixed. (Therefore Hilbert's hotel is
    potential infinity.)
    What we refer to as infinite isn't variable.
    The number of guests/rooms in Hilbert's hotel is infinite but can
    grow.
    That is variable infinity.
    The number of rooms is fixed,
    One more guest requires one more room.
    *Which is already there*. We are not building new rooms, we are
    moving the guests.

    otherwise it weren't interesting.
    It is interestimng only insofar as it shows that adherents of set theory
    are ready to believe every shit.
    Do you believe Hilbert's Hotel cannot accomodate *any* new guests?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Thu Mar 27 21:41:39 2025
    Am Thu, 27 Mar 2025 21:07:18 +0100 schrieb WM:
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    Substance is simply the elements of the set. The amount of substance
    is the number of elements.
    You seem to mean the cardinality of the set.
    Not at all! Cardinality concerns only definable elements.
    That is all that mathematicians talk about.

    This number exists also for actually infinite sets but cannot be
    expressed by natural numbers.
    We only know that ∀k,n ∈ ℕ_def: |ℕ|/k > n.
    |N|/k is undefined.
    It is undefined *as a finite number*. But it is defined by |N|/(k-1) >
    |N|/k > |N|/(k+1).
    Like I was saying, they are infinite.

    You're saying that the "substance" isn't a property of a set as such,
    it's a property of a relationship between a superset and a subset.
    The relative amount of substance can be determined. The set {1, 2, 3}
    has more substance than the set {father, mother}.
    You mean it has a larger cardinality.
    For finite sets cardinality is a meaningful notion expressing the number
    of elements. But I dislike it because it is often extended to cover
    infinite sets where it does not describe the number of elements.

    For example, to get the "substance" of N with respect to Q, you could
    embed it in the superset Q: You'd get something like: {0, 1, 1/2, 2,
    1/3, 3, 1/4, 2/3, 3/2, 4, 1/5, 5, ....}. Then this "substance" would
    come out as zero.
    Nearly. It is smaller than any definable fraction.
    Crank talk.
    Ideas surpassing your knowledge by far.

    So, to come back to my original example, the "substance" of {0, 4, 8,
    12, 16, ...} wrt N is 1/4.
    Yes.
    The substance of {1, 3, 5, 7, 9, ...} wrt {0, 1/2, 1, 3/2, 2, 5/2, 3,
    ....} is also 1/4.
    Yes.
    Their "subtances" are thus the same.
    Yes. Their amounts of substance, to be precise.
    Or their cardinality, to be even more precise.
    No, to be imprecise. Their numbers of elements differ but their
    cardinality is the same.

    If you consider it with cool blood, then you will recognize that all
    pairs of a bijection with ℕ are defined within a finite initial
    segment [0, n]. That is true for every n. But the infinity lies in the
    successors which are undefined.
    That's pure baloney. Every element of a bijection is an ordered pair
    of an element of set 1 and an element of set 2. Each element of these
    sets occurs in exactly one ordered pair. There is no need to obfuscate
    this definition with considerations of finite initial segments or
    infinity or what have you.
    It is correct and shows that cardinality is nonsense.

    Tend to yes, but not reaching it.
    I thought you just said you had a degree in maths. But you don't
    seem to understand the process of limits (a bit like John Gabriel
    didn't when he was still around).
    0/oo = 0. 1/oo is smaller than every definable fraction.
    More crank talk. Ordinary arithmetic is not defined on infinity. And
    "smaller than every definable fraction" is zero.
    Study surreal and hyperreal numbers which appear even in modern
    mathematics.
    Again, thanks for confirming your "dark numbers" are infinite (or infinitesimal). They are definitely not reals, and we are not
    talking specifically about hyperreals. (You could have just said
    your "substance" is a hyperreal number up front and avoided all
    these misunderstandings.)

    The Bourbakis have tried to exorcize the potential infinite from
    mathematics. Your teachers have been taught by them or their pupils.
    "Potentially infinite" doesn't belong in mathematics. It's not of any
    use, and causes only obfuscation and confusion, not illumination.
    Look, you don't know much. Not even surreal and hyperreal numbers. Why
    should I take your word on other topics as fact?
    Since when do you know about them? (That's rhetorical btw.)

    What everybody else refers to as infinte, you seem to want to call
    "potentially infinite".
    The potential infinite is a variable finite. Cantor's actual infinity
    is not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    Hilbert's hotel is infinite, not "variably finite".
    Then its number of guests and of rooms could not change.
    It doesn't.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Thu Mar 27 21:45:57 2025
    Am Thu, 27 Mar 2025 21:11:00 +0100 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    The number of [...] rooms in Hilbert's hotel is infinite but [...]
    grow[s].
    No, it doesn't.
    And the number of guests?
    Depends on how you look at it. The hotel is always "full" in that all
    rooms are occupied; yet it can always accomodate more guests (but not uncountably many). There are "exactly" as many rooms as guests at any
    point, so far as that makes sense for infinities.

    Real fools like really counterintuitive "results".
    The whole point of Hilbert's Hotel is illustrating the counterintuitivity
    of infinite cardinalities.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Thu Mar 27 21:50:18 2025
    Am Thu, 27 Mar 2025 21:15:39 +0100 schrieb WM:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual
    infinity is not variable but fixed. (Therefore Hilbert's hotel is
    potential infinity.)
    What we refer to as infinite isn't variable.
    The number of guests/rooms in Hilbert's hotel is infinite but can
    grow. That is variable infinity.
    You are mistaken. (Countable) infinity stays the same when you add
    finite and countably infinite numbers to it.
    That proves that cardinality is nonsense. When a new guest arrives, then
    the number of guests grows by 1.
    It's just counterintuitive, which is excusable, as opposed to your
    wilfull ignorance. Yes, but the new number is also still equal, it
    does not become "more infinite"/uncountable.

    Thus in Hilbert's hotel,
    although all the rooms are occupied, one of these rooms can be vacated
    to make room for a new guest without expelling an existing guest.
    Real fools are really delighted by counterintuitive results.
    Natural fools hold their intuition above all.

    Adding that new guest doesn't change the number of guests in the hotel,
    or the number of rooms required.
    Real fools are really delighted by counterintuitive results.
    That's what makes math fun.

    See many of Jim's posts over the last few days for details.
    There is only one important detail, namely that lossless exchanges cause losses. It is sufficient to reject every intelligent being.
    That's a misrepresentation.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

    --- SoupGate-Win32 v1.05
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  • From Moebius@21:1/5 to All on Fri Mar 28 01:35:34 2025
    Am 27.03.2025 um 18:50 schrieb Alan Mackenzie:
    Moebius <invalid@example.invalid> wrote:

    WM doesn't have a degree in mathematics.

    He denied not having one. Most of the time, people don't outright lie
    on Usenet. They twist and turn, answering direct questiongs evasively
    and inadequately, and assert half truths.

    My working theory at the moment is that WM has some university degree
    which had a small component of mathematics, but that part of his degree didn't cover rigorous analysis or rigorous set theory, or anything much
    else rigorous.

    "Von 1973 bis 1977 studierte Mückenheim Physik mit den Nebenfächern Mathematik, Astronomie und Chemie an der Georg-August-Universität
    Göttingen. Sein Diplomstudium schloss er bei Martin Schumacher mit einer Diplomarbeit über das kernphysikalische Thema Der Zerfall des 122J ab.
    1979 erwarb er in der gleichen Göttinger Arbeitsgruppe den Doktorgrad im
    Fach Physik mit einer Dissertation über elastische Photonstreuung an
    Uran, einem Thema aus dem Gebiet der Vakuumpolarisation." (Wikipedia)

    [From 1973 to 1977, Mückenheim studied physics with minors in
    mathematics, astronomy, and chemistry at the Georg August University of Göttingen. He completed his studies under Martin Schumacher with a
    thesis on the nuclear physics topic of "The Decay of 122J." In 1979, he
    earned his doctorate in physics in the same Göttingen research group
    with a dissertation on elastic photon scattering by uranium, a topic in
    the field of vacuum polarization.]

    So he studied _4 years_ "physics with minors in mathematics, astronomy,
    and chemistry", go figure!

    He clearly lacks a proper foundation in math.

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  • From Moebius@21:1/5 to All on Fri Mar 28 01:55:17 2025
    Am 27.03.2025 um 20:31 schrieb WM:
    Am 27.03.2025 um 15:59 schrieb joes:

    The number of rooms is fixed,

    One more guest requires one more room.

    Nope.

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  • From Moebius@21:1/5 to All on Fri Mar 28 01:59:48 2025
    Am 27.03.2025 um 21:07 schrieb WM:

    For finite sets cardinality is a meaningful notion expressing the number
    of elements.
    For infinite sets it is a "generalisation" of the notion "number of
    elements".

    Hint: "In mathematics, the cardinality of a set is the number of its
    elements. The cardinality of a set may also be called its size, when no confusion with other notions of size is possible. Beginning in the late
    19th century, this concept of size was generalized to infinite sets,
    allowing one to distinguish between different types of infinity and to
    perform arithmetic on them." (Wikipedia)

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  • From Moebius@21:1/5 to All on Fri Mar 28 02:02:29 2025
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:


    The number of [...] rooms in Hilbert's hotel is infinite but [...]
    grow[s].

    No, it doesn't.

    And the number of guests?

    Is still the same: aleph_0.

    It's just the "reality" (->Cantor) of guests that has grown by one. :-)

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  • From Moebius@21:1/5 to All on Fri Mar 28 06:02:46 2025
    Am 28.03.2025 um 02:02 schrieb Moebius:
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:


    The number of [...] rooms in Hilbert's hotel is infinite but [...]
    grow[s].

    No, it doesn't.

    And the number of guests?

    Is still the same: aleph_0.

    It's just the "reality" (->Cantor) of guests that has grown by one. :-)

    In other words, {g_0, g_1, g_2, g_3, ...} has more "substance"
    Moebius) than {g_1, g_2, g_3, ...}, though both sets have the same cardinality (i.e. cardinal number).

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  • From WM@21:1/5 to All on Fri Mar 28 08:34:15 2025
    Am 28.03.2025 um 02:02 schrieb Moebius:
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:


    The number of [...] rooms in Hilbert's hotel is infinite but [...]
    grow[s].

    No, it doesn't.

    And the number of guests?

    Is still the same: aleph_0.

    It's just the "reality" (->Cantor) of guests that has grown by one. :-)

    Set theory cannot describe reality. :-(
    Mathematics is expected to be able to describe reality. :-)

    Regards, WM

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  • From joes@21:1/5 to All on Fri Mar 28 10:39:18 2025
    Am Fri, 28 Mar 2025 08:34:15 +0100 schrieb WM:
    Am 28.03.2025 um 02:02 schrieb Moebius:
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    The number of [...] rooms in Hilbert's hotel is infinite but [...] >>>>>> grow[s].
    No, it doesn't.
    And the number of guests?
    Is still the same: aleph_0.
    It's just the "reality" (->Cantor) of guests that has grown by one. :-)
    Set theory cannot describe reality. :-(
    Mathematics is expected to be able to describe reality. :-)

    Now you're just confusing the technical and colloquial meaning. You
    should have stuck with "substance", but then you could simply talk
    about supersets. That's what Cantor referred to off-handedly as
    "Realität". No such term is used in mathematics, and still it does
    describe the world remarkably well - not that infinite sets
    physically exist.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From Alan Mackenzie@21:1/5 to Jim Burns on Fri Mar 28 11:22:00 2025
    Jim Burns <james.g.burns@att.net> wrote:
    On 3/27/2025 1:50 PM, Alan Mackenzie wrote:
    Moebius <invalid@example.invalid> wrote:
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:



    Crank talk.
    You don't understand limits, as I've already said.
    Have you really got a degree in mathematics?
    It seems unlikely.

    WM doesn't have a degree in mathematics.

    He denied not having one.
    Most of the time,

    Hmmm.

    Most of the time,
    people don't outright lie on Usenet.
    They twist and turn,
    answering direct questiongs evasively and inadequately,
    and assert half truths.

    My working theory at the moment is that
    WM has some university degree which had
    a small component of mathematics, but
    that part of his degree didn't cover
    rigorous analysis or rigorous set theory,
    or anything much else rigorous.

    https://de.wikipedia.org/wiki/Wolfgang_M%C3%BCckenheim
    [Google->Eng]
    ⎛ From 1973 to 1977, Mückenheim studied physics with
    ⎜ minors in mathematics, astronomy and chemistry ...

    ⎜ In 1979, he obtained his doctorate in physics with
    ⎜ a dissertation on elastic photon scattering on
    ⎝ the ¹²²uranium, ...

    OK. For some reason, it didn't occur to me that WM would have a
    Wikipedia page. If only he'd stuck to posting knowledgeably about his
    area of expertise. That would surely be very interesting.

    ⎛ For the record, my (JB's) own formal education ends with
    ⎜ a bachelor's degree in physics and
    ⎝ minors in mathematics and computer science.

    But somehow you've managed to pick up the fundamentals of maths. :-)

    For what it's worth,
    on paper, Mückenheim is more qualified than I am.
    I suspect that that irks him to no end.

    His outpourings on this newsgroup (as well as on its German
    counterpart) pretty much rule out systematic study of the foundations
    of mathematics.

    He studied at Göttingen, which was at the forefront of mathematical development in the past, and likely is in the present too. Surely it is
    likely that any maths course there, even as a subsidiary part of another
    main degree, is going to cover the fundamentals pretty thoroughly.

    I am honestly mystified by
    what I need to explain to Mückenheim,
    someone who apparently has taken
    upper.level courses in mathematics.

    Am I unusual in having had to prove things
    in such courses, for homework and for tests?

    Not at all.

    But I have a theory.

    There once was a poster of the crankish persuasion,
    convinced that he was going to prove
    Fermat's Last Theorem at a highschool level of difficulty.
    He seemed to know very little mathematics.

    Yes, I remember. I even remember his name.

    I had some reason to look back over
    his much.earlier posts, and
    I was surprised to find that
    that, much _earlier_ he apparently knew _more_
    than the same (?) poster later, _after_ years of
    arguing mathematics with mathematicians.

    I noticed the same pattern with Archimedes Plutonium. I posted to and
    lurked on this newsgroup for a short while ~25 years ago, and my memory
    of him when I came back to the group quite recently was of a cogent
    thinker. I was at first surprised and disappointed to see the
    deterioration.

    My theory is that
    trying to defend bullshit rots the brain.

    Interesting. Maybe the constant mental stress of defending the said
    bullshit against continual correction over many years takes its toll.

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Fri Mar 28 16:24:40 2025
    Am 28.03.2025 um 08:34 schrieb WM:

    Set theory cannot describe reality. :-(

    If you say so. :-)

    On the other hand, it suffices that it can be used for _mathematics_. :-)

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  • From Alan Mackenzie@21:1/5 to invalid@no.org on Fri Mar 28 15:45:47 2025
    WM <invalid@no.org> wrote:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity is >>>>> not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.

    The number of guests/rooms in Hilbert's hotel is infinite but can
    grow. That is variable infinity.

    You are mistaken. (Countable) infinity stays the same when you add
    finite and countably infinite numbers to it.

    That proves that cardinality is nonsense. When a new guest arrives,
    then the number of guests grows by 1.

    Yes indeed. There were aleph-0 guests beforehand, the new guest arrives growing that number by 1, giving aleph-0. Why do you find this so
    difficult to understand?

    Thus in Hilbert's hotel, although all the rooms are occupied, one of
    these rooms can be vacated to make room for a new guest without
    expelling an existing guest.

    Real fools are really delighted by counterintuitive results.

    You've run out of mathematics, so you resort to ad hominem. Not very
    good. Hint: the person who devised "Hilbert's hotel" was in no sense a
    fool.

    Adding that new guest doesn't change the number of guests in the
    hotel, or the number of rooms required.

    Real fools are really delighted by counterintuitive results.

    See many of Jim's posts over the last few days for details.

    There is only one important detail, namely that lossless exchanges
    cause losses. It is sufficient to reject every intelligent being.

    An infinite process of lossless exchanges can cause loss, as we have
    seen.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Alan Mackenzie@21:1/5 to invalid@no.org on Fri Mar 28 16:32:55 2025
    WM <invalid@no.org> wrote:
    Am 27.03.2025 um 12:18 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    [ .... ]

    For finite sets cardinality is a meaningful notion expressing the number
    of elements. But I dislike it because it is often extended to cover
    infinite sets where it does not describe the number of elements.

    You have not proposed any other measure for the "number of elements" of
    an infinite set. At least, not in a mathematically useful way.

    [ .... ]

    So, to come back to my original example, the "substance" of {0, 4, 8,
    12, 16, ...} wrt N is 1/4.

    Yes.

    The substance of {1, 3, 5, 7, 9, ...} wrt {0, 1/2, 1, 3/2, 2, 5/2, 3,
    ....} is also 1/4.

    Yes.

    Their "subtances" are thus the same.

    Yes. Their amounts of substance, to be precise.

    Or their cardinality, to be even more precise.

    No, to be imprecise. Their numbers of elements differ but their
    cardinality is the same.

    So tell us, O wise one, how many elements are there in {1, 3, 5, 7, 9,
    ...}? And how many elements in {0, 4, 8, 12, 16, ...}? Which of these
    two numbers is bigger, and why?

    [ .... ]

    Tend to yes, but not reaching it.

    I thought you just said you had a degree in maths. But you don't seem to >>>> understand the process of limits (a bit like John Gabriel didn't when he >>>> was still around).

    0/oo = 0. 1/oo is smaller than every definable fraction.

    More crank talk. Ordinary arithmetic is not defined on infinity. And
    "smaller than every definable fraction" is zero.

    Study surreal and hyperreal numbers which appear even in modern
    mathematics.

    [ .... ]

    Look, you don't know much. Not even surreal and hyperreal numbers. Why
    should I take your word on other topics as fact?>

    For your information, I bought a copy of the first edition of Conway's
    "On Numbers and Games" back in 1979 and read it, before surreal numbers
    were even called that. And in surreal numbers "smaller than every
    definable fraction" is also zero. There is no notion of "undefinable
    number" in the surreals any more than there is in the reals or the
    natural numbers.

    [ .... ]

    The potential infinite is a variable finite. Cantor's actual infinity
    is not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)

    Hilbert's hotel is infinite, not "variably finite".

    Then its number of guests and of rooms could not change.

    That's your intuition misleading you again.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Jim Burns@21:1/5 to All on Fri Mar 28 14:03:45 2025
    On 3/28/2025 3:34 AM, WM wrote:
    Am 28.03.2025 um 02:02 schrieb Moebius:
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    The number of [...] rooms in Hilbert's hotel
    is infinite but [...] grow[s].

    No, it doesn't.

    And the number of guests?

    Is still the same: aleph_0.

    It's just the "reality" (->Cantor) of guests
    that has grown by one. :-)

    Set theory cannot describe reality. :-(

    Set theory describes the Cantorian reality of sets.

    Set theory makes claims certainly true about
    what set theory's claims are true about.
    Which, granted, is circular.
    But is also certainly true.

    Mathematics is expected to
    be able to describe reality. :-)

    Some of mathematics is known to not.describe
    Wignerian reality.
    Sorting the "good" description from the "bad" is
    what observation and experiments are for.

    Observation and experiments underdetermine
    Wignerian reality.

    Mathematical theories of physical reality associate
    (observed) Wignerian reality with
    (necessary) Cantorian reality, which associates with
    (predicted) Wignerian reality.

    The only part of _that scheme_ which we are
    (mostly) discussing is the Cantorian.reality.part.

    Other discussions are possible.
    Do we "really" observe our observations,
    or are we brains in vats being tricked by
    some all.powerful demon?
    Why are our
    Wignerian(Cantorian(Wignerian))) predictions
    so good? Etc.

    Cantorian descriptions are certainly true about
    what they describe.
    That's a very low bar to get over,
    but they don't need more.

    Cantorian consequences are certainly true about
    whatever they're about
    IF
    they are claims (somewhere, anywhere) in
    a finite sequence of claims with no first.false claim.

    My claim about Cantorian consequences is NOT
    a claim about, for example, photon scattering.
    It is a claim about
    claims about, for example, photon scattering.
    Specifically, it is about finite sequences of claims,
    whatever they're about.

    In a finite sequence of things,
    if a thing x has property P
    then some thing y is first having property P.
    That's true, because of what 'finite' means,
    even if the things are _claims_
    about some indefinite one.of.infinitely.many
    and Property P is being.false.

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  • From WM@21:1/5 to Jim Burns on Wed Apr 2 15:41:32 2025
    On 27.03.2025 22:01, Jim Burns wrote:

    My theory is that
    trying to defend bullshit rots the brain.

    No doubt. Only a very rotten brain can seriously propose losses in
    lossless exchanges.

    Regards, WM

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  • From WM@21:1/5 to joes on Wed Apr 2 15:58:05 2025
    On 27.03.2025 22:31, joes wrote:
    Am Thu, 27 Mar 2025 20:31:16 +0100 schrieb WM:
    Am 27.03.2025 um 15:59 schrieb joes:
    Am Wed, 26 Mar 2025 21:28:52 +0100 schrieb WM:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual
    infinity is not variable but fixed. (Therefore Hilbert's hotel is
    potential infinity.)
    What we refer to as infinite isn't variable.
    The number of guests/rooms in Hilbert's hotel is infinite but can
    grow.
    That is variable infinity.
    The number of rooms is fixed,
    One more guest requires one more room.
    *Which is already there*. We are not building new rooms, we are
    moving the guests.

    That is only possible if it is possible, i.e., ifinfinity is potential
    never occupied completely. That contradicts the completeness of Cantor's bijections.

    otherwise it weren't interesting.
    It is interesting only insofar as it shows that adherents of set theory
    are ready to believe every shit.
    Do you believe Hilbert's Hotel cannot accomodate *any* new guests?

    If it is actually infinite, then no. If it can accomodate every new
    guest, then it is never completely filled.

    Regards, WM


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  • From WM@21:1/5 to joes on Wed Apr 2 16:14:09 2025
    On 27.03.2025 22:45, joes wrote:
    Am Thu, 27 Mar 2025 21:11:00 +0100 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    The number of [...] rooms in Hilbert's hotel is infinite but [...]
    grow[s].
    No, it doesn't.
    And the number of guests?
    Depends on how you look at it. The hotel is always "full" in that all
    rooms are occupied; yet it can always accomodate more guests (but not uncountably many). There are "exactly" as many rooms as guests at any
    point, so far as that makes sense for infinities.

    That means not fixed infinity. The alternative is potential infinity.

    Real fools like really counterintuitive "results".
    The whole point of Hilbert's Hotel is illustrating the counterintuitivity
    of infinite cardinalities.

    It illustrates the confusion between potential and actual infinity.

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe
    steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S. 152]

    If a new element enters, then the old order must be given up. A new
    number is required.

    Regards, WM

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  • From WM@21:1/5 to Moebius on Wed Apr 2 16:18:53 2025
    On 28.03.2025 01:55, Moebius wrote:
    Am 27.03.2025 um 20:31 schrieb WM:
    Am 27.03.2025 um 15:59 schrieb joes:

    The number of rooms is fixed,

    One more guest requires one more room.

    Nope.

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe
    steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S. 152]

    If another element enters, then something must change. That is possible
    in potential infinity.

    Regards, WM

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  • From WM@21:1/5 to Moebius on Wed Apr 2 16:20:42 2025
    On 28.03.2025 01:59, Moebius wrote:
    Am 27.03.2025 um 21:07 schrieb WM:

    For finite sets cardinality is a meaningful notion expressing the
    number of elements.
    For infinite sets it is a "generalisation" of the notion "number of elements".

    Hint: "In mathematics, the cardinality of a set is the number of its elements.

    This is wrong because an element can be added without changing the
    cardinality.

    Regards, WM

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  • From WM@21:1/5 to Moebius on Wed Apr 2 16:25:05 2025
    On 28.03.2025 02:02, Moebius wrote:

    It's just the "reality" (->Cantor) of guests that has grown by one. :-)

    Obviously the reality or substance is not correctly measured by cardinality.

    Regards, WM

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  • From WM@21:1/5 to Moebius on Wed Apr 2 16:28:25 2025
    On 28.03.2025 06:02, Moebius wrote:
    Am 28.03.2025 um 02:02 schrieb Moebius:
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:


    The number of [...] rooms in Hilbert's hotel is infinite but [...] >>>>>> grow[s].

    No, it doesn't.

    And the number of guests?

    Is still the same: aleph_0.

    It's just the "reality" (->Cantor) of guests that has grown by one. :-)

    In other words, {g_0, g_1, g_2, g_3, ...} has more "substance"
    Moebius) than {g_1, g_2, g_3, ...}, though both sets have the same cardinality (i.e. cardinal number).

    In other words, cardinality cannot distinguish between the full
    substances of sets because it counts only the first elements.

    Regards, WM

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  • From WM@21:1/5 to joes on Wed Apr 2 16:31:33 2025
    On 28.03.2025 11:39, joes wrote:
    Am Fri, 28 Mar 2025 08:34:15 +0100 schrieb WM:
    Am 28.03.2025 um 02:02 schrieb Moebius:
    Am 27.03.2025 um 21:11 schrieb WM:
    Am 26.03.2025 um 23:18 schrieb Moebius:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    The number of [...] rooms in Hilbert's hotel is infinite but [...] >>>>>>> grow[s].
    No, it doesn't.
    And the number of guests?
    Is still the same: aleph_0.
    It's just the "reality" (->Cantor) of guests that has grown by one. :-)
    Set theory cannot describe reality. :-(
    Mathematics is expected to be able to describe reality. :-)

    Now you're just confusing the technical and colloquial meaning. You
    should have stuck with "substance", but then you could simply talk
    about supersets. That's what Cantor referred to off-handedly as
    "Realität". No such term is used in mathematics, and still it does
    describe the world remarkably well

    It does not describe anything of reality.

    - not that infinite sets
    physically exist.

    If they did, the mistakes of set theory would show up when set theory
    was applied to them.

    Regards, WM



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  • From WM@21:1/5 to Jim Burns on Wed Apr 2 16:38:01 2025
    On 27.03.2025 22:01, Jim Burns wrote:

    https://de.wikipedia.org/wiki/Wolfgang_M%C3%BCckenheim
    [Google->Eng]
    ⎛ From 1973 to 1977, Mückenheim studied physics with
    ⎜ minors in mathematics, astronomy and chemistry ...

    ⎜ In 1979, he obtained his doctorate in physics with
    ⎜ a dissertation on elastic photon scattering on
    ⎝ the ¹²²uranium, ...

    Hey, that would have given 10 Nobel prizes at once.

    Regards, WM

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  • From WM@21:1/5 to Moebius on Wed Apr 2 16:45:02 2025
    On 28.03.2025 16:24, Moebius wrote:
    Am 28.03.2025 um 08:34 schrieb WM:

    Set theory cannot describe reality. :-(

    If you say so. :-)

    On the other hand, it suffices that it can be used for _mathematics_. :-)

    Infinite set theory is not valid for any useful mathematics. Only for a
    cage of fools who entertain themselves and each other by mutually
    admiring their nonsense.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Wed Apr 2 16:51:56 2025
    On 28.03.2025 16:45, Alan Mackenzie wrote:
    WM <invalid@no.org> wrote:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual infinity is >>>>>> not variable but fixed. (Therefore Hilbert's hotel is potential
    infinity.)
    What we refer to as infinite isn't variable.

    The number of guests/rooms in Hilbert's hotel is infinite but can
    grow. That is variable infinity.

    You are mistaken. (Countable) infinity stays the same when you add
    finite and countably infinite numbers to it.

    That proves that cardinality is nonsense. When a new guest arrives,
    then the number of guests grows by 1.

    Yes indeed. There were aleph-0 guests beforehand, the new guest arrives growing that number by 1, giving aleph-0. Why do you find this so
    difficult to understand?

    It is not at all difficult to understand. Difficult to understand is
    only why cardinality is used at all. It is worthless because it cannot
    describe changes of substance. If there are |ℕ| natural numbers, then
    there are |ℕ|^2 positive fractions. The cardinality is the same because
    it counts only the first elements. Potential infinity. Otherwise it
    could not overlook the big difference.

    There is only one important detail, namely that lossless exchanges
    cause losses. It is sufficient to reject every intelligent being.

    An infinite process of lossless exchanges can cause loss, as we have
    seen.

    No. You have not seen it. You are mistaken and try to maintain your
    mistakes by "limits" which are not used in Cantor's theory: "so daß
    jedes Element der Menge an einer bestimmten Stelle dieser Reihe steht"
    [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S. 152]

    Regards, WM
    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Wed Apr 2 17:02:33 2025
    On 28.03.2025 17:32, Alan Mackenzie wrote:

    So tell us, O wise one, how many elements are there in {1, 3, 5, 7, 9,
    ...}? And how many elements in {0, 4, 8, 12, 16, ...}? Which of these
    two numbers is bigger, and why?

    |ℕ|/2 > |ℕ|/4.

    Regards, WM

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  • From WM@21:1/5 to joes on Thu Apr 3 15:49:04 2025
    On 02.04.2025 21:39, joes wrote:
    There are never empty rooms, all rooms are
    always occupied,

    Are there new guests?

    that's kinda the point. And yet it can accommodate
    a countable number of guests, unlike if it were finite.

    You confuse the cardinal number and the reality. More rooms or more
    guests have same cardinal number. But that is irrelevant because the
    cardinal number says nothing. It is a pity however that many, many
    thousands of young students have been stultified to helieve what you
    wrote above. That is not counterintuitive but it is simply bullshit.

    Regards, WM

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Thu Apr 3 14:40:25 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 28.03.2025 17:32, Alan Mackenzie wrote:

    So tell us, O wise one, how many elements are there in {1, 3, 5, 7, 9,
    ...}? And how many elements in {0, 4, 8, 12, 16, ...}? Which of these
    two numbers is bigger, and why?

    |ℕ|/2 > |ℕ|/4.

    Start out with a set of natural numbers. Multiply each member by four,
    giving a new set. You'd have us believe that the new set contains fewer elements than the original set. Baloney.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From Moebius@21:1/5 to All on Thu Apr 3 17:36:36 2025
    Am 03.04.2025 um 16:40 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 28.03.2025 17:32, Alan Mackenzie wrote:

    So tell us, O wise one, how many elements are there in {1, 3, 5, 7, 9,
    ...}? And how many elements in {0, 4, 8, 12, 16, ...}? Which of these
    two numbers is bigger, and why?

    |ℕ|/2 > |ℕ|/4.

    Start out with a set of natural numbers. Multiply each member by four, giving a new set. You'd have us believe that the new set contains fewer elements than the original set. Baloney.

    Consider the sets IN = {0, 1, 2, 3, ...} and IN* = {{n} : n e IN} =
    {{0}, {1}, {2}, ...}.

    Mückenheim agreed that then |IN| = |IN*|, since this is "obvous" (for
    him), due to the "rule of construction" (WM) or whatever.

    Then I told him, that IN actually is defined due to Zermelo, i.e. IN =
    {{}, {{}}, {{{}}}, ...} with 0 = {}, 1 = {0}, 2 = {1}, etc. (in general
    n' = {n}).

    This means that (surprise!) IN* = {1, 2, 3, ...}.

    But in Mückenheim's world |{1, 2, 3, ...}| = |IN|-1 =/= |IN| = |{0, 1,
    2, 3, ...}|. Hence "actually" |IN*| =/= |IN|. Contradiction (one might
    think)!

    WM: <bla bla bla> (i.e. crank talk).

    Regards, WM


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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Thu Apr 3 19:10:14 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 28.03.2025 16:45, Alan Mackenzie wrote:
    WM <invalid@no.org> wrote:
    Am 26.03.2025 um 22:38 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 26.03.2025 21:06, joes wrote:
    Am Wed, 26 Mar 2025 20:36:40 +0100 schrieb WM:

    The potential infinite is a variable finite. Cantor's actual
    infinity is not variable but fixed. (Therefore Hilbert's hotel
    is potential infinity.)
    What we refer to as infinite isn't variable.

    The number of guests/rooms in Hilbert's hotel is infinite but can
    grow. That is variable infinity.

    You are mistaken. (Countable) infinity stays the same when you add
    finite and countably infinite numbers to it.

    That proves that cardinality is nonsense. When a new guest arrives,
    then the number of guests grows by 1.

    Yes indeed. There were aleph-0 guests beforehand, the new guest arrives
    growing that number by 1, giving aleph-0. Why do you find this so
    difficult to understand?

    It is not at all difficult to understand. Difficult to understand is
    only why cardinality is used at all.

    Those two sentences contradict eachother. Cardinality is used because it
    is a sensible way of comparing the size of sets.

    It is worthless because it cannot describe changes of substance. If
    there are |ℕ| natural numbers, then there are |ℕ|^2 positive fractions.

    Yes, and aleph_0^2 = aleph_0. There are as many positive fractions as
    natural numbers. This was proven by Cantor. That you don't understand
    the proof is your problem, not ours.

    The cardinality is the same because it counts only the first elements.

    That's a meaningless concatenation of words. Cardinalities do not count.
    What you might mean by "only the first elements" is completely obscure.

    Potential infinity. Otherwise it could not overlook the big difference.

    Just "infinite" is a lot simpler, hence is used in modern mathematics.

    There is only one important detail, namely that lossless exchanges
    cause losses. It is sufficient to reject every intelligent being.

    An infinite process of lossless exchanges can cause loss, as we have
    seen.

    No. You have not seen it.

    What makes you think you know what I have and have not seen?

    You are mistaken and try to maintain your mistakes by "limits" which
    are not used in Cantor's theory:

    I'm quite sure Cantor was enirely familiar with the theory of limits. It
    seems you are not.

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this sequence." That has no relevance to anything at issue here. In
    particular, it has no relevance to the loss of your favourite set element caused by an infinite sequence of transpositions.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

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  • From WM@21:1/5 to Alan Mackenzie on Thu Apr 3 22:17:33 2025
    On 03.04.2025 16:40, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 28.03.2025 17:32, Alan Mackenzie wrote:

    So tell us, O wise one, how many elements are there in {1, 3, 5, 7, 9,
    ...}? And how many elements in {0, 4, 8, 12, 16, ...}? Which of these
    two numbers is bigger, and why?

    |ℕ|/2 > |ℕ|/4.

    Start out with a set of natural numbers. Multiply each member by four, giving a new set. You'd have us believe that the new set contains fewer elements than the original set.

    Fact. Ifff the natural numbers are an actually infinite set, then its
    elements are invariable and fixed. By multiplication no larger numbers
    can be created. What you have in mind is a potentially infinite set.

    Let me explain in detail:

    Cantor created the sequence of the ordinal numbers by means of his first
    and second generation principle: 0, 1, 2, 3, ..., ω, ω+1, ω+2, ω+3, ..., 2ω, 2ω+1, 2ω+2, 2ω+3, ..., 3ω, ... . In 1884 he exchanged the positions
    of multiplier and the number to be multiplied with the result

    0, 1, 2, 3, ..., ω, ω+1, ω+2, ω+3, ..., ω*2, ω*2+1, ω*2+2, ω*2+3, ...,
    ω*3, ... .

    This sequence, except its very first terms, has no relevance for
    classical mathematics. But it is important for set theory that in actual infinity nothing fits between ℕ and ω. Likewise before ω*2 and ω*3 there is no empty space. According to Hilbert we can simply count beyond the
    infinite by a quite natural and uniquely determined, consistent
    continuation of the ordinary counting in the finite. But we would
    proceed even faster, when instead of counting, we doubled the numbers.
    This leads to the central issue: Multiply every element of the set ℕ by 2

    {1, 2, 3, ...}*2 = {2, 4, 6, ...} .

    The density of the natural numbers on the real axis is greater than the
    density of the even natural numbers. Therefore the doubled natural
    numbers cover twice as many space than before. What is the result of
    doubling? Either all doubled numbers are natural numbers, then not all
    natural numbers have been doubled. Natural numbers not available before
    have been created. This is possible only based on potential infinity. Or
    all natural numbers have been doubled, then the result stretches
    farther, namely beyond all natural numbers.

    It is more suggestive to double the set ℕ U {ω} = {1, 2, 3, ..., ω} with the result

    {1, 2, 3, ..., ω}*2 = {2, 4, 6, ..., ω*2} .

    What elements fall between ω and ω*2? What size has the interval between
    2ℕ and ω*2? The natural answer is (0, ω]*2 = (0, ω*2] with ω or ω+1 amidst. The number of doubled natural numbers is precisely |ℕ|. But half
    of the doubled numbers are no longer natural numbers; they surpass ω. If
    all natural numbers including all even numbers are doubled and if
    doubling increases the value for all natural numbers because n < 2n,
    then not all doubled even numbers fit below ω. Natural numbers greater
    than all even natural numbers however are not possible.

    Every other result would violate symmetry and beauty of mathematics, for instance the claim that the result would be ℕ U {ω, ω*2}. All numbers between ω and ω*2, which are precisely as many as in ℕ between 0 and ω, would not be in the result? Every structure must be doubled! Like the
    interval [1, 5] of lengths 4 by doubling gets [1, 5]*2 = [2, 10] of
    length 8, the interval (0, ω]*2 gets (0, ω*2] with ω*2 = ω + ω =/= ω where the whole interval between 0 and ω*2 is evenly filled with even
    numbers like the whole interval between 0 and ω is evenly filled with
    natural numbers before multiplication. On the ordinal axis the numbers
    0, ω, ω*2, ω*3, ... have same distances because same number of ordinals
    lie between them. This means that contrary to the collection of visible natural numbers ℕ_def which only are relevant in classical mathematics
    the whole set ℕ is not closed under multiplication. Some natural numbers
    can become transfinite by multiplication.

    This resembles the displacement of the interval (0, 1] by one point to
    the left-hand side such that the interval [0, 1) is covered. Of course
    these natural numbers are dark like every result of ω/k with k ∈ ℕ_def, for instance ω/2 or ω/10^10^100. It is with certainty excluded to reduce positive real numbers by division to negative numbers. This
    impossibility might be taken as an argument that it is also impossible
    to produce transfinite numbers by multiplying dark natural numbers. This argument would be tantamount to denying actual infinity at all.

    Regards, WM

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  • From WM@21:1/5 to Alan Mackenzie on Thu Apr 3 22:28:44 2025
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    It is not at all difficult to understand. Difficult to understand is
    only why cardinality is used at all.

    Those two sentences contradict eachother. Cardinality is used because it
    is a sensible way of comparing the size of sets.

    No.

    It is worthless because it cannot describe changes of substance. If
    there are |ℕ| natural numbers, then there are |ℕ|^2 positive fractions.

    Yes, and aleph_0^2 = aleph_0. There are as many positive fractions as natural numbers.

    This is easily contradicted by observing that 1/2 is not a natural
    number while all natural numbers are fractions.

    This was proven by Cantor. That you don't understand
    the proof is your problem, not ours.

    I understand that you are duped. And I have explained why. Every pair of
    the bijection has almost all elements as successors.

    The cardinality is the same because it counts only the first elements.

    That's a meaningless concatenation of words.

    It is a pity that you can't understand. Every natural number that you
    can use in a bijection has finitely many predecessors but infinitely
    many successors which will never be used.
    An infinite process of lossless exchanges can cause loss, as we have
    seen.

    No. You have not seen it.

    What makes you think you know what I have and have not seen?

    I know your mistakes and their origin.

    You are mistaken and try to maintain your mistakes by "limits" which
    are not used in Cantor's theory:

    I'm quite sure Cantor was enirely familiar with the theory of limits.

    But he did not use them in his bijections.

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe
    steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this sequence." That has no relevance to anything at issue here. In
    particular, it has no relevance to the loss of your favourite set element caused by an infinite sequence of transpositions.

    Just this is excluded. Only definite positions are admitted. No evasion
    into the infinite.

    Regards, WM

    --- SoupGate-Win32 v1.05
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  • From Moebius@21:1/5 to All on Fri Apr 4 01:26:24 2025
    Am 03.04.2025 um 21:10 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe
    steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this sequence." That has no relevance to anything at issue here. [...]
    WM is mixing up things Cantor expressed with his own muddled "thoughts".
    In short: He's quite confused.

    --- SoupGate-Win32 v1.05
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  • From Moebius@21:1/5 to All on Fri Apr 4 03:49:52 2025
    Am 03.04.2025 um 21:10 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe
    steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this sequence." That has no relevance to anything at issue here. [...]

    WM is mixing up things Cantor expressed with his (WM's) own muddled
    "thoughts". In short: He's quite confused.

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  • From Moebius@21:1/5 to All on Fri Apr 4 04:34:30 2025
    Am 04.04.2025 um 03:49 schrieb Moebius:
    Am 03.04.2025 um 21:10 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe >>> steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this
    sequence."  That has no relevance to anything at issue here. [...]

    WM is mixing up things Cantor expressed with his (WM's) own muddled "thoughts". In short: He's quite confused.

    Did I mention that he's an asshole full of shit?

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  • From WM@21:1/5 to Moebius on Fri Apr 4 14:57:35 2025
    On 04.04.2025 03:49, Moebius wrote:
    Am 03.04.2025 um 21:10 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe >>> steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this
    sequence."  That has no relevance to anything at issue here. [...]

    WM is mixing up things Cantor expressed

    Did Cantor express this in connection with and describing the topic just
    under discussion, namely the bijection of a set with all natural numbers?

    Regards, WM

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  • From Alan Mackenzie@21:1/5 to wolfgang.mueckenheim@tha.de on Fri Apr 4 16:41:55 2025
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    It is not at all difficult to understand. Difficult to understand is
    only why cardinality is used at all.

    Those two sentences contradict eachother. Cardinality is used because it
    is a sensible way of comparing the size of sets.

    No.

    You're wrong.

    It is worthless because it cannot describe changes of substance. If
    there are |ℕ| natural numbers, then there are |ℕ|^2 positive fractions.

    Yes, and aleph_0^2 = aleph_0. There are as many positive fractions as
    natural numbers.

    This is easily contradicted by observing that 1/2 is not a natural
    number while all natural numbers are fractions.

    It is not contradicted. There is a 1-1 correspondence between positive fractions and natural numbers.

    This was proven by Cantor. That you don't understand the proof is
    your problem, not ours.

    I understand that you are duped. And I have explained why. Every pair of
    the bijection has almost all elements as successors.

    Eh?? What the heck are you going on about? Hint: a bijection is a set
    of pairs. It is not ordered.

    The cardinality is the same because it counts only the first elements.

    That's a meaningless concatenation of words.

    It is a pity that you can't understand.

    It's a pity you can't express yourself clearly; or don't want to.

    Every natural number that you can use in a bijection has finitely many predecessors but infinitely many successors which will never be used.

    Wrong. Every natural number in a bijection of N with some set gets
    "used", by definition of bijection.

    An infinite process of lossless exchanges can cause loss, as we have
    seen.

    No. You have not seen it.

    What makes you think you know what I have and have not seen?

    I know your mistakes and their origin.

    You would do better to concentrate on your own mistakes, which are many.

    You are mistaken and try to maintain your mistakes by "limits" which
    are not used in Cantor's theory:

    I'm quite sure Cantor was enirely familiar with the theory of limits.

    But he did not use them in his bijections.

    Borders on the meaningless.

    "so daß jedes Element der Menge an einer bestimmten Stelle dieser Reihe >>> steht" [E. Zermelo: "Georg Cantor – Gesammelte Abhandlungen
    mathematischen und philosophischen Inhalts", Springer, Berlin (1932) S.
    152]

    "So that each element of the set stands at a definite position of this
    sequence." That has no relevance to anything at issue here. In
    particular, it has no relevance to the loss of your favourite set element
    caused by an infinite sequence of transpositions.

    Just this is excluded. Only definite positions are admitted. No evasion
    into the infinite.

    You mean, you're only allowing a finite number of transpositions? In
    that case, the distinguished element indeed does not disappear.

    Regards, WM

    --
    Alan Mackenzie (Nuremberg, Germany).

    --- SoupGate-Win32 v1.05
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  • From WM@21:1/5 to Alan Mackenzie on Fri Apr 4 21:36:53 2025
    On 04.04.2025 18:41, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    It is not at all difficult to understand. Difficult to understand is
    only why cardinality is used at all.

    Those two sentences contradict eachother. Cardinality is used because it >>> is a sensible way of comparing the size of sets.

    No.

    You're wrong.

    You are caught in a world of stupidity. Set theorists have damaged the
    honour of human intellect even more than Pope Pius XII.

    When an element is added to a set, then this set is no longer the same
    but different because the number of its members is different.

    This is easily contradicted by observing that 1/2 is not a natural
    number while all natural numbers are fractions.

    It is not contradicted. There is a 1-1 correspondence between positive fractions and natural numbers.

    Only for natural numbers which have less predecessors than successors.

    I understand that you are duped. And I have explained why. Every pair of
    the bijection has almost all elements as successors.

    Eh?? What the heck are you going on about? Hint: a bijection is a set
    of pairs. It is not ordered.

    The natural numbers are ordered. Therefore the bijection is ordered.

    "thus we get the epitome (ω) of all real algebraic numbers [...] and
    with respect to this order" Georg Cantor – Gesammelte Abhandlungen mathematischen und philosophischen Inhalts", Springer, Berlin (1932) p. 116]
    Every natural number that you can use in a bijection has finitely many
    predecessors but infinitely many successors which will never be used.

    Wrong.

    Name an exception.

    Just this is excluded. Only definite positions are admitted. No evasion
    into the infinite.

    You mean, you're only allowing a finite number of transpositions?

    No, but all the infinitely many indices of transpositions are finite.

    Regards, WM



    In
    that case, the distinguished element indeed does not disappear.

    Regards, WM


    --- SoupGate-Win32 v1.05
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  • From Moebius@21:1/5 to All on Sat Apr 5 01:04:37 2025
    Am 04.04.2025 um 18:41 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    Difficult to understand is only why cardinality is used at all. [WM]
    No, it's not. I mean, except for Mr. Mückenheim.
    Cardinality is used because it is a sensible way of comparing the size of sets.

    Right.

    No. [WM]

    You're wrong.

    Yes.

    Every pair of the bijection has almost all elements as successors. [WM]

    So what? WM seems to think that this fact doesn't allow for a bijection,
    this old fool.

    Eh?? What the heck are you going on about? Hint: a bijection is a set
    of pairs. It is not ordered.

    Right. But WM like to considered (countable) _ordered_ sets. This way he
    can mix up processes ("ordered by their steps") with bijections.

    For example:

    Every natural number that you can use in a bijection has finitely many
    predecessors but infinitely many successors which will never be used.

    See?
    Wrong. Every natural number in a bijection of N with some set gets
    "used", by definition of bijection.

    Indeed!
    .

    --- SoupGate-Win32 v1.05
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  • From Moebius@21:1/5 to All on Sat Apr 5 02:05:54 2025
    Am 04.04.2025 um 18:41 schrieb Alan Mackenzie:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    Difficult to understand is only why cardinality is used at all. [WM]
    No, it's not. I mean, except for Mr. Mückenheim.
    Cardinality is used because it is a sensible way of comparing the size of sets.

    Right.

    No. [WM]

    You're wrong.

    Yes.

    Every pair of the bijection has almost all elements as successors. [WM]

    So what? WM seems to think that this fact doesn't allow for a bijection,
    this old fool.

    Eh?? What the heck are you going on about? Hint: a bijection is a set
    of pairs. It is not ordered.

    Right. But WM likes to considered (countable) _ordered_ sets. This way
    he can mix up processes ("ordered by their steps") with bijections.

    For example:

    Every natural number that you can use in a bijection has finitely many
    predecessors but infinitely many successors which will never be used.

    See?
    Wrong. Every natural number in a bijection of N with some set gets
    "used", by definition of bijection.

    Indeed!
    .

    --- SoupGate-Win32 v1.05
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  • From WM@21:1/5 to FromTheRafters on Sat Apr 5 20:55:52 2025
    On 04.04.2025 23:12, FromTheRafters wrote:
    WM wrote on 4/4/2025 :

    You are caught in a world of stupidity. Set theorists have damaged the
    honour of human intellect even more than Pope Pius XII.

    When an element is added to a set, then this set is no longer the same
    but different because the number of its members is different.

    How do you know that they are not 'the same'?

    A set containing element x is not the same as a set not containing
    element x.

    No bijection perhaps?

    There are no definable infinite bijections. Every natural number that
    you can define in a bijection has finitely many predecessors but
    infinitely many successors which will never be defined.

    Regards, WM

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  • From WM@21:1/5 to FromTheRafters on Sat Apr 5 22:51:32 2025
    On 05.04.2025 21:08, FromTheRafters wrote:
    WM was thinking very hard :
    On 04.04.2025 23:12, FromTheRafters wrote:
    WM wrote on 4/4/2025 :

    You are caught in a world of stupidity. Set theorists have damaged
    the honour of human intellect even more than Pope Pius XII.

    When an element is added to a set, then this set is no longer the
    same but different because the number of its members is different.

    How do you know that they are not 'the same'?

    A set containing element x is not the same as a set not containing
    element x.

    Then of course they are not "the same" but are they equivalent in size?

    According to Cantor they are equivalent or have same cardinality. But
    that is not a useful notion *because* sets with different number of
    members are called equivalent.

    Regards, WM

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  • From joes@21:1/5 to All on Sun Apr 13 08:25:27 2025
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    It is not at all difficult to understand. Difficult to understand is
    only why cardinality is used at all.
    Those two sentences contradict eachother. Cardinality is used because
    it is a sensible way of comparing the size of sets.

    It is worthless because it cannot describe changes of substance. If
    there are |ℕ| natural numbers, then there are |ℕ|^2 positive
    fractions.
    Yes, and aleph_0^2 = aleph_0. There are as many positive fractions as
    natural numbers.
    This is easily contradicted by observing that 1/2 is not a natural
    number while all natural numbers are fractions.
    No, that is a subset relation („reality”). The identity function is obviously not a bijection from N to Q.

    This was proven by Cantor. That you don't understand the proof is your
    problem, not ours.
    I understand that you are duped. And I have explained why. Every pair of
    the bijection has almost all elements as successors.
    Bijections aren’t ordered.

    The cardinality is the same because it counts only the first elements.
    That's a meaningless concatenation of words.
    It is a pity that you can't understand. Every natural number that you
    can use in a bijection has finitely many predecessors but infinitely
    many successors which will never be used.
    No, a bijection can be an infinite set of pairs - must be, if the sets
    are infinite.

    "So that each element of the set stands at a definite position of this
    sequence." That has no relevance to anything at issue here. In
    particular, it has no relevance to the loss of your favourite set
    element caused by an infinite sequence of transpositions.
    Just this is excluded. Only definite positions are admitted. No evasion
    into the infinite.
    Then you cannot talk about the limit.

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

    --- SoupGate-Win32 v1.05
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  • From joes@21:1/5 to All on Sun Apr 13 08:20:10 2025
    Am Thu, 03 Apr 2025 22:17:33 +0200 schrieb WM:
    On 03.04.2025 16:40, Alan Mackenzie wrote:
    WM <wolfgang.mueckenheim@tha.de> wrote:
    On 28.03.2025 17:32, Alan Mackenzie wrote:

    So tell us, O wise one, how many elements are there in {1, 3, 5, 7,
    9, ...}? And how many elements in {0, 4, 8, 12, 16, ...}? Which of
    these two numbers is bigger, and why?
    |ℕ|/2 > |ℕ|/4.
    Start out with a set of natural numbers. Multiply each member by four,
    giving a new set. You'd have us believe that the new set contains
    fewer elements than the original set.
    Fact. Ifff the natural numbers are an actually infinite set, then its elements are invariable and fixed.
    How else could it be.

    By multiplication no larger numbers
    can be created. What you have in mind is a potentially infinite set.

    Let me explain in detail:
    Cantor created the sequence of the ordinal numbers by means of his first
    and second generation principle:
    0, 1, 2, 3, ..., ω, ω+1, ω+2, ω+3, ..., ω*2, ω*2+1, ω*2+2, ω*2+3, ..., ω*3, ... .
    This sequence, except its very first terms, has no relevance for
    classical mathematics. But it is important for set theory that in actual infinity nothing fits between ℕ and ω. Likewise before ω*2 and ω*3
    there is no empty space.
    What do „fits” and „space” mean?

    According to Hilbert we can simply count beyond the
    infinite by a quite natural and uniquely determined, consistent
    continuation of the ordinary counting in the finite. But we would
    proceed even faster, when instead of counting, we doubled the numbers.
    This leads to the central issue: Multiply every element of the set ℕ by
    2
    {1, 2, 3, ...}*2 = {2, 4, 6, ...} .

    The density of the natural numbers on the real axis is greater than the density of the even natural numbers.
    In which sense? There are infinitely many of either.

    Therefore the doubled natural numbers cover twice as many space than
    before.
    Again, how? How much?

    What is the result of
    doubling? Either all doubled numbers are natural numbers, then not all natural numbers have been doubled.
    Why? Every even number has a natural half its value.

    Natural numbers not available before
    have been created. This is possible only based on potential infinity. Or
    all natural numbers have been doubled, then the result stretches
    farther, namely beyond all natural numbers.
    No, there is no natural number whose double is larger than ω.
    Your mistake is to think of infinity as a really big number of the same
    kind as naturals, but it is rather more like a type or a special point.

    It is more suggestive to double the set ℕ U {ω} = {1, 2, 3, ..., ω}
    with the result
    {1, 2, 3, ..., ω}*2 = {2, 4, 6, ..., ω*2} .
    What elements fall between ω and ω*2?
    Where is ω?

    What size has the interval between 2ℕ and ω*2?
    What is the interval between two sets?

    The natural answer is (0, ω]*2 = (0, ω*2] with ω or ω+1
    amidst.
    No, that would be two consecutive infinities. You can do that, but not
    with f(x)=2x and not without violating the order.

    The number of doubled natural numbers is precisely |ℕ|. But half
    of the doubled numbers are no longer natural numbers; they surpass ω. If
    all natural numbers including all even numbers are doubled and if
    doubling increases the value for all natural numbers because n < 2n,
    then not all doubled even numbers fit below ω.
    Yes they do. The product of two naturals is also a natural.

    Natural numbers greater
    than all even natural numbers however are not possible.

    Every other result would violate symmetry and beauty of mathematics, for instance the claim that the result would be ℕ U {ω, ω*2}. All numbers between ω and ω*2, which are precisely as many as in ℕ between 0 and ω, would not be in the result? Every structure must be doubled!
    The „structure” (order type) of N is ω and not ω*2.

    Like the
    interval [1, 5] of lengths 4 by doubling gets [1, 5]*2 = [2, 10] of
    length 8, the interval (0, ω]*2 gets (0, ω*2] with ω*2 = ω + ω =/= ω where the whole interval between 0 and ω*2 is evenly filled with even numbers like the whole interval between 0 and ω is evenly filled with natural numbers before multiplication. On the ordinal axis the numbers
    0, ω, ω*2, ω*3, ... have same distances because same number of ordinals lie between them.
    How do you define subtraction for ordinals?

    This means that contrary to the collection of visible
    natural numbers ℕ_def which only are relevant in classical mathematics
    the whole set ℕ is not closed under multiplication. Some natural numbers can become transfinite by multiplication.
    No, the union of the set called N and those numbers you have added is not closed. That’s your problem, not that of mathematics.

    This resembles the displacement of the interval (0, 1] by one point to
    the left-hand side such that the interval [0, 1) is covered.
    What is „one point”? Can you give an explicit function?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From WM@21:1/5 to joes on Sun Apr 13 13:35:20 2025
    On 13.04.2025 10:25, joes wrote:
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    Yes, and aleph_0^2 = aleph_0. There are as many positive fractions as
    natural numbers.
    This is easily contradicted by observing that 1/2 is not a natural
    number while all natural numbers are fractions.
    No,

    Yes.

    This was proven by Cantor. That you don't understand the proof is your
    problem, not ours.
    I understand that you are duped. And I have explained why. Every pair of
    the bijection has almost all elements as successors.
    Bijections aren’t ordered.

    Bijections with ℕ are ordered by the well-ordered set ℕ.

    The cardinality is the same because it counts only the first elements.
    That's a meaningless concatenation of words.
    It is a pity that you can't understand. Every natural number that you
    can use in a bijection has finitely many predecessors but infinitely
    many successors which will never be used.
    No, a bijection can be an infinite set of pairs - must be, if the sets
    are infinite.

    Every pair of the bijection has almost all elements as successors.

    "So that each element of the set stands at a definite position of this
    sequence." That has no relevance to anything at issue here. In
    particular, it has no relevance to the loss of your favourite set
    element caused by an infinite sequence of transpositions.
    Just this is excluded. Only definite positions are admitted. No evasion
    into the infinite.
    Then you cannot talk about the limit.

    So it is. Bijections with ℕ are well-ordered and have no limit but only
    all definable terms.

    Regards, WM


    --- SoupGate-Win32 v1.05
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  • From WM@21:1/5 to joes on Sun Apr 13 13:30:54 2025
    On 13.04.2025 10:20, joes wrote:
    Am Thu, 03 Apr 2025 22:17:33 +0200 schrieb WM:
    On 03.04.2025 16:40, Alan Mackenzie wrote:

    Ifff the natural numbers are an actually infinite set, then its
    elements are invariable and fixed.
    How else could it be.

    The alternative is potential infinity.

    The density of the natural numbers on the real axis is greater than the
    density of the even natural numbers.
    In which sense? There are infinitely many of either.

    For all infinitely many finite lengths the densities are 2 to 1.

    Therefore the doubled natural numbers cover twice as many space than
    before.
    Again, how? How much?

    They cover the ordinal axis between 0 and 2ω evenly.
    Natural numbers not available before
    have been created. This is possible only based on potential infinity. Or
    all natural numbers have been doubled, then the result stretches
    farther, namely beyond all natural numbers.
    No, there is no natural number whose double is larger than ω.

    Wrong if infinity is actaul.

    It is more suggestive to double the set ℕ U {ω} = {1, 2, 3, ..., ω}
    with the result
    {1, 2, 3, ..., ω}*2 = {2, 4, 6, ..., ω*2} .
    What elements fall between ω and ω*2?
    Where is ω?

    On the ordinal axis immediately after all natural numbers.

    Regards, WM

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  • From WM@21:1/5 to joes on Sun Apr 13 17:37:57 2025
    On 13.04.2025 10:25, joes wrote:
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    This was proven by Cantor. That you don't understand the proof is your
    problem, not ours.
    I understand that you are duped. And I have explained why. Every pair of
    the bijection has almost all elements as successors.
    Bijections aren’t ordered.

    Bijections with well-ordered sets are well ordered. Compare Cantor:
    § 12. Die wohlgeordneten Mengen ........ 312
    § 13. Die Abschnitte wohlgeordneter Mengen ............. 314
    § 14. Die Ordnungszahlen wohlgeordneter Mengen ........ 320

    Only definite positions are admitted. No evasion
    into the infinite.
    Then you cannot talk about the limit.

    There is none.

    Regards, WM


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  • From WM@21:1/5 to FromTheRafters on Sun Apr 13 17:29:32 2025
    On 13.04.2025 14:00, FromTheRafters wrote:
    on 4/13/2025, WM supposed :

    Bijections with ℕ are ordered by the well-ordered set ℕ.

    The set N is not ordered, you want omega for the ordered set of naturals.

    The well-ordered set ℕ is well ordered. Compare
    § 12. Die wohlgeordneten Mengen ..... 312
    § 13. Die Abschnitte wohlgeordneter Mengen .... 314
    § 14. Die Ordnungszahlen wohlgeordneter Mengen .. 320
    [Cantor, collected works]

    Regards, WM

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  • From joes@21:1/5 to All on Mon Apr 14 09:03:52 2025
    Am Sun, 13 Apr 2025 13:30:54 +0200 schrieb WM:
    On 13.04.2025 10:20, joes wrote:
    Am Thu, 03 Apr 2025 22:17:33 +0200 schrieb WM:
    On 03.04.2025 16:40, Alan Mackenzie wrote:

    Ifff the natural numbers are an actually infinite set, then its
    elements are invariable and fixed.
    How else could it be.
    The alternative is potential infinity.
    The set of naturals does not change; every number either is or is not
    included in it.

    The density of the natural numbers on the real axis is greater than
    the density of the even natural numbers.
    In which sense? There are infinitely many of either.
    For all infinitely many finite lengths the densities are 2 to 1.
    Aha! And for the one infinite length we get the undefined expression
    inf/inf.

    Therefore the doubled natural numbers cover twice as many space than
    before.
    Again, how? How much?
    They cover the ordinal axis between 0 and 2ω evenly.
    So there are infinitely large even naturals?

    Natural numbers not available before have been created. This is
    possible only based on potential infinity. Or all natural numbers have
    been doubled, then the result stretches farther, namely beyond all
    natural numbers.
    No, there is no natural number whose double is larger than ω.
    Wrong if infinity is actaul.
    Just no. It would have to be larger than ω (=infinite) itself. Half an infinity is still infinite.

    It is more suggestive to double the set ℕ U {ω} = {1, 2, 3, ..., ω}
    with the result
    {1, 2, 3, ..., ω}*2 = {2, 4, 6, ..., ω*2} .
    What elements fall between ω and ω*2?
    Where is ω?
    On the ordinal axis immediately after all natural numbers.
    No, I mean in the second set? ω/2 is not even defined. Or do you think
    the naturals form consecutive infinities like
    1, 2, 3, …, ω/ω, ω/(ω-1), ω/(ω-2), …, ω/3, ω/2, ω ?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Mon Apr 14 08:51:29 2025
    Am Sun, 13 Apr 2025 17:37:57 +0200 schrieb WM:
    On 13.04.2025 10:25, joes wrote:
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    This was proven by Cantor. That you don't understand the proof is
    your problem, not ours.
    I understand that you are duped. And I have explained why. Every pair
    of the bijection has almost all elements as successors.
    Bijections aren’t ordered.
    Bijections with well-ordered sets are well ordered.
    You can do that, but what does it buy you? It would be infinite even
    without an order. It’s not necessary for your argument.

    Only definite positions are admitted. No evasion into the infinite.
    Then you cannot talk about the limit.
    There is none.
    Dude, you are talking about the result of an infinite process. Are
    you saying it diverges?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From joes@21:1/5 to All on Mon Apr 14 12:12:36 2025
    Am Mon, 14 Apr 2025 13:56:01 +0200 schrieb WM:
    On 14.04.2025 10:51, joes wrote:
    Am Sun, 13 Apr 2025 17:37:57 +0200 schrieb WM:
    On 13.04.2025 10:25, joes wrote:
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    This was proven by Cantor. That you don't understand the proof is >>>>>> your problem, not ours.
    I understand that you are duped. And I have explained why. Every
    pair of the bijection has almost all elements as successors.
    Bijections aren’t ordered.
    Bijections with well-ordered sets are well ordered.
    You can do that, but what does it buy you? It would be infinite even
    without an order. It’s not necessary for your argument.
    Order is necessary to convince intelligent readers that almost all terms
    are successors of any defined term.
    You could just say that the bijection is between infinite sets. Then your
    claim boils down to „those don’t exist”, which you haven’t provided any reasoning for.

    Only definite positions are admitted. No evasion into the infinite.
    Then you cannot talk about the limit.
    There is none.
    Dude, you are talking about the result of an infinite process. Are you
    saying it diverges?
    It is claimed by Cantor that all pairs of the bijection exist at defined places without limit.
    So? What do you claim?

    --
    Am Sat, 20 Jul 2024 12:35:31 +0000 schrieb WM in sci.math:
    It is not guaranteed that n+1 exists for every n.

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  • From WM@21:1/5 to joes on Mon Apr 14 14:06:05 2025
    On 14.04.2025 11:03, joes wrote:
    Am Sun, 13 Apr 2025 13:30:54 +0200 schrieb WM:
    On 13.04.2025 10:20, joes wrote:
    Am Thu, 03 Apr 2025 22:17:33 +0200 schrieb WM:
    On 03.04.2025 16:40, Alan Mackenzie wrote:

    Ifff the natural numbers are an actually infinite set, then its
    elements are invariable and fixed.
    How else could it be.
    The alternative is potential infinity.
    The set of naturals does not change; every number either is or is not included in it.

    The set of defined natural changes like the set of known prime numbers.
    If oly defined naturals exist, then we have a potentially infinite
    collection.

    The density of the natural numbers on the real axis is greater than
    the density of the even natural numbers.
    In which sense? There are infinitely many of either.
    For all infinitely many finite lengths the densities are 2 to 1.
    Aha! And for the one infinite length we get the undefined expression
    inf/inf.

    No, we get the limit (here it is appropriate to use it) of the function
    2, 2, 2, ... .

    Therefore the doubled natural numbers cover twice as many space than
    before.
    Again, how? How much?
    They cover the ordinal axis between 0 and 2ω evenly.
    So there are infinitely large even naturals?

    No, they are not natural numbers because all natural numbers are finite,
    i.e., less than ω. But by counting we can pass ω, according to Hilbert.
    Why shouldn't we pass it by multiplying?

    Natural numbers not available before have been created. This is
    possible only based on potential infinity. Or all natural numbers have >>>> been doubled, then the result stretches farther, namely beyond all
    natural numbers.
    No, there is no natural number whose double is larger than ω.
    Wrong if infinity is actual.
    Just no. It would have to be larger than ω (=infinite) itself. Half an infinity is still infinite.

    ω/n is larger than every definable natnumber but not larger than any natnumber.

    It is more suggestive to double the set ℕ U {ω} = {1, 2, 3, ..., ω} >>>> with the result
    {1, 2, 3, ..., ω}*2 = {2, 4, 6, ..., ω*2} .
    What elements fall between ω and ω*2?
    Where is ω?
    On the ordinal axis immediately after all natural numbers.
    No, I mean in the second set? ω/2 is not even defined.

    It is a dark number.

    Or do you think
    the naturals form consecutive infinities like
    1, 2, 3, …, ω/ω, ω/(ω-1), ω/(ω-2), …, ω/3, ω/2, ω ?

    ω/ω = 1.

    We get 1, 2, 3, ..., ω/n, ..., ω-1, ω

    Regards, WM

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  • From WM@21:1/5 to joes on Mon Apr 14 13:56:01 2025
    On 14.04.2025 10:51, joes wrote:
    Am Sun, 13 Apr 2025 17:37:57 +0200 schrieb WM:
    On 13.04.2025 10:25, joes wrote:
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    This was proven by Cantor. That you don't understand the proof is
    your problem, not ours.
    I understand that you are duped. And I have explained why. Every pair
    of the bijection has almost all elements as successors.
    Bijections aren’t ordered.
    Bijections with well-ordered sets are well ordered.
    You can do that, but what does it buy you? It would be infinite even
    without an order. It’s not necessary for your argument.

    Order is necessary to convince intelligent readers that almost all terms
    are successors of any defined term. Stupid readers however will never understand.

    Only definite positions are admitted. No evasion into the infinite.
    Then you cannot talk about the limit.
    There is none.
    Dude, you are talking about the result of an infinite process. Are
    you saying it diverges?

    It is claimed by Cantor that all pairs of the bijection exist at defined
    places without limit.

    Regards, WM


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  • From WM@21:1/5 to joes on Mon Apr 14 14:20:59 2025
    On 14.04.2025 14:12, joes wrote:
    Am Mon, 14 Apr 2025 13:56:01 +0200 schrieb WM:
    On 14.04.2025 10:51, joes wrote:
    Am Sun, 13 Apr 2025 17:37:57 +0200 schrieb WM:
    On 13.04.2025 10:25, joes wrote:
    Am Thu, 03 Apr 2025 22:28:44 +0200 schrieb WM:
    On 03.04.2025 21:10, Alan Mackenzie wrote:

    This was proven by Cantor. That you don't understand the proof is >>>>>>> your problem, not ours.
    I understand that you are duped. And I have explained why. Every
    pair of the bijection has almost all elements as successors.
    Bijections aren’t ordered.
    Bijections with well-ordered sets are well ordered.
    You can do that, but what does it buy you? It would be infinite even
    without an order. It’s not necessary for your argument.
    Order is necessary to convince intelligent readers that almost all terms
    are successors of any defined term.
    You could just say that the bijection is between infinite sets. Then your claim boils down to „those don’t exist”,

    No, my "claim" is a basic truth. Define a number which has less
    successors than predecessors. Fail.

    Infinite sets do exist. But dark numbers cannot be put in bijections
    (except simplest identical mappings).

    It is claimed by Cantor that all pairs of the bijection exist at defined
    places without limit.
    So? What do you claim?

    Only definable pairs exist.

    Regards, WM


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