• Re: =?iso-8859-7?Q?Flibble=A2s?= Leap: Why Behavioral Divergence Implie

    From Mr Flibble@21:1/5 to Richard Heathfield on Sun May 11 14:48:35 2025
    On Sun, 11 May 2025 15:44:44 +0100, Richard Heathfield wrote:

    On 11/05/2025 14:21, Mr Flibble wrote:
    This reframing dissolves the paradox by making the Halting Problem
    itself an ill-posed question.

    "P is a syntactically correct program in some well-defined
    Turing-complete language. Does P stop when it is applied to this data
    X?" is a meaningful and well-formed question. It's not a Carrollian
    question like Olcott's "what time is it, yes or no?" It has a sensible answer. Either P stops for X, or it doesn't.

    It's a question that can in many (but not all) cases be answered quickly
    and easily enough (and correctly) by humans, often requiring no more
    than a brief glimpse. (I say 'not all' only because it is not beyond the
    wit of mankind to trump up extraordinarily complicated and deliberately obfuscated code that might easily defeat a programmer's casual glance.)

    Some simple examples in K&R C:

    main(){}

    main(){for(;;);}

    main(){puts("Hello");}

    #include <stdio.h>
    main(){long c=0;int ch; while((ch = getchar()) !=
    EOF)++c;printf("%ld\n", c);} /* input: the complete works of Shakespeare
    */

    Any competent C programmer can solve these at a glance - Halts, Loops,
    Halts, Halts, in that order - so why shouldn't a programmer be able to?

    The Halting Problem asks a more complicated question. ``Is it possible
    to write a program that answers the above question for arbitrary P and arbitrary X?"

    Again, the question is meaningful and well-formed. It's syntactically
    and grammatically adequate, and anyone claiming not to know what it
    means is laying themselves open to a charge of disingenuousness. The
    only difficult part is the answer, but there's nothing
    self-contradictory or self-referential or paradoxical about the
    question.

    It is insufficient for the question to be syntactically correct, it needs
    to be SEMANTICALLY correct too.

    /Flibble

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  • From Mr Flibble@21:1/5 to Richard Heathfield on Sun May 11 14:59:56 2025
    On Sun, 11 May 2025 15:44:44 +0100, Richard Heathfield wrote:

    but there's nothing self-contradictory or self-referential or
    paradoxical about the question.

    That is simply untrue.

    /Flibble

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  • From Mr Flibble@21:1/5 to Richard Heathfield on Sun May 11 15:49:26 2025
    On Sun, 11 May 2025 16:47:09 +0100, Richard Heathfield wrote:

    On 11/05/2025 16:34, Mr Flibble wrote:
    On Sun, 11 May 2025 16:25:14 +0100, Richard Heathfield wrote:

    For a question to be semantically incorrect, it takes more than just
    you and your allies to be unhappy with it.

    For a question to be semantically correct, it takes more than just you
    and your allies to be happy with it.

    Indeed. It has to have meaning. It does. That meaning has to be
    understood by sufficiently intelligent people. It is.

    You don't like the question. I get that. I don't know /why/ you don't
    like it, because all your explanations to date have been complete
    expletive deleted. For a Usenet article to be semantically correct, it
    helps if your readers can understand what the <exp. del.> you're talking about.

    What I get from your stand is that you agree with olcott that a 'pathological' input halts... no, never halts... well, you can't decide between you, but you're agreed that it's definitely decidable, right?

    Re-read the OP for my answer:

    Flibble’s Leap: Why Behavioral Divergence Implies a Type Distinction in
    the Halting Problem ===========================================================================================

    Summary
    -------
    Flibble argues that the Halting Problem's undecidability proof is built on
    a category (type) error: it assumes a program and its own representation
    (as a finite string) are interchangeable. This assumption fails under simulating deciders, revealing a type distinction through behavioral divergence. As such, all deciders must respect this boundary, and diagonalization becomes ill-formed. This reframing dissolves the paradox
    by making the Halting Problem itself an ill-posed question.

    1. Operational Evidence of Type Distinction -------------------------------------------
    - When a program (e.g., `DD()`) is passed to a simulating halt decider
    (`HHH`), it leads to infinite recursion.
    - This behavior differs from direct execution (e.g., a crash due to a
    stack overflow).
    - This divergence shows that the program (as code) and its representation
    (as data) are operationally distinct.
    - Therefore, treating them as the same "type" (as Turing's proof does)
    leads to inconsistency.

    2. Generalization to All Deciders
    ---------------------------------
    - If simulation reveals this type mismatch, then no valid decider can rely
    on conflating program and representation.
    - Diagonalization (e.g., defining D(x) = if H(x,x) then loop else halt) necessarily crosses the type boundary.
    - The contradiction in the Halting Problem arises from this type error,
    not from inherent undecidability.
    - Hence, the Halting Problem is ill-defined for self-referential input.

    3. Comparisons to Other Formal Systems
    --------------------------------------
    - In type-theoretic systems (like Coq or Agda), such self-reference is disallowed:
    - Programs must be well-typed.
    - Self-referential constructs like `H(x, x)` are unrepresentable if they would lead to paradox.
    - In category theory, morphisms must respect domain/codomain boundaries:
    - Reflexive constructions require stratification to avoid logical inconsistency.

    4. Conclusion
    -------------
    - The Halting Problem depends on self-reference and diagonalization.
    - If these constructs are blocked due to type/category errors, the proof
    breaks down.
    - Thus, the Halting Problem isn’t undecidable—it’s malformed when it crosses type boundaries.
    - This is not a refutation of Turing, but a reformulation of the problem
    under more disciplined typing rules.

    This model mirrors how Russell’s Paradox was avoided in modern logic: not
    by solving the contradiction, but by redefining the terms that made the contradiction possible.

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  • From Mr Flibble@21:1/5 to olcott on Sun May 11 16:05:27 2025
    On Sun, 11 May 2025 10:56:02 -0500, olcott wrote:

    On 5/11/2025 10:49 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 16:47:09 +0100, Richard Heathfield wrote:

    On 11/05/2025 16:34, Mr Flibble wrote:
    On Sun, 11 May 2025 16:25:14 +0100, Richard Heathfield wrote:

    For a question to be semantically incorrect, it takes more than just >>>>> you and your allies to be unhappy with it.

    For a question to be semantically correct, it takes more than just
    you and your allies to be happy with it.

    Indeed. It has to have meaning. It does. That meaning has to be
    understood by sufficiently intelligent people. It is.

    You don't like the question. I get that. I don't know /why/ you don't
    like it, because all your explanations to date have been complete
    expletive deleted. For a Usenet article to be semantically correct, it
    helps if your readers can understand what the <exp. del.> you're
    talking about.

    What I get from your stand is that you agree with olcott that a
    'pathological' input halts... no, never halts... well, you can't
    decide between you, but you're agreed that it's definitely decidable,
    right?

    Re-read the OP for my answer:

    Flibble’s Leap: Why Behavioral Divergence Implies a Type Distinction in
    the Halting Problem
    ===========================================================================================

    Summary -------
    Flibble argues that the Halting Problem's undecidability proof is built
    on a category (type) error: it assumes a program and its own
    representation (as a finite string) are interchangeable. This
    assumption fails under simulating deciders, revealing a type
    distinction through behavioral divergence. As such, all deciders must
    respect this boundary, and diagonalization becomes ill-formed. This
    reframing dissolves the paradox by making the Halting Problem itself an
    ill-posed question.

    1. Operational Evidence of Type Distinction
    -------------------------------------------
    - When a program (e.g., `DD()`) is passed to a simulating halt decider
    (`HHH`), it leads to infinite recursion.
    - This behavior differs from direct execution (e.g., a crash due to a
    stack overflow).

    The directly executed DD() simply halts because HHH has stopped the
    infinite recursion that it specifies on its second recursive call.

    That behaviour is due to a decision you have made, that I disagree with,
    the correct thing to do is to allow infinite recursion to manifest as
    stack overflow rather than return an artificial halting result.


    DD emulated by HHH according to the rules of the x86 language cannot
    possibly halt. Because all deciders are required to report on what their finite string input specifies HHH must reject DD as non-halting.

    The category error precludes a decision being made as the problem is ill- formed.

    /Flibble

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  • From Mr Flibble@21:1/5 to Richard Heathfield on Sun May 11 15:34:44 2025
    On Sun, 11 May 2025 16:25:14 +0100, Richard Heathfield wrote:

    For a question to be semantically incorrect, it takes more than just you
    and your allies to be unhappy with it.

    For a question to be semantically correct, it takes more than just you and
    your allies to be happy with it.

    Your turn, mate.

    /Flibble

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  • From Mr Flibble@21:1/5 to olcott on Sun May 11 16:59:34 2025
    On Sun, 11 May 2025 11:49:51 -0500, olcott wrote:

    On 5/11/2025 11:05 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 10:56:02 -0500, olcott wrote:

    On 5/11/2025 10:49 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 16:47:09 +0100, Richard Heathfield wrote:

    On 11/05/2025 16:34, Mr Flibble wrote:
    On Sun, 11 May 2025 16:25:14 +0100, Richard Heathfield wrote:

    For a question to be semantically incorrect, it takes more than
    just you and your allies to be unhappy with it.

    For a question to be semantically correct, it takes more than just >>>>>> you and your allies to be happy with it.

    Indeed. It has to have meaning. It does. That meaning has to be
    understood by sufficiently intelligent people. It is.

    You don't like the question. I get that. I don't know /why/ you
    don't like it, because all your explanations to date have been
    complete expletive deleted. For a Usenet article to be semantically
    correct, it helps if your readers can understand what the <exp.
    del.> you're talking about.

    What I get from your stand is that you agree with olcott that a
    'pathological' input halts... no, never halts... well, you can't
    decide between you, but you're agreed that it's definitely
    decidable, right?

    Re-read the OP for my answer:

    Flibble’s Leap: Why Behavioral Divergence Implies a Type Distinction >>>> in the Halting Problem

    ===========================================================================================

    Summary -------
    Flibble argues that the Halting Problem's undecidability proof is
    built on a category (type) error: it assumes a program and its own
    representation (as a finite string) are interchangeable. This
    assumption fails under simulating deciders, revealing a type
    distinction through behavioral divergence. As such, all deciders must
    respect this boundary, and diagonalization becomes ill-formed. This
    reframing dissolves the paradox by making the Halting Problem itself
    an ill-posed question.

    1. Operational Evidence of Type Distinction
    -------------------------------------------
    - When a program (e.g., `DD()`) is passed to a simulating halt
    decider (`HHH`), it leads to infinite recursion.
    - This behavior differs from direct execution (e.g., a crash due to a
    stack overflow).

    The directly executed DD() simply halts because HHH has stopped the
    infinite recursion that it specifies on its second recursive call.

    That behaviour is due to a decision you have made, that I disagree
    with,
    the correct thing to do is to allow infinite recursion to manifest as
    stack overflow rather than return an artificial halting result.


    That fails to meet the spec of a termination analyzer.

    Nevertheless it is impossible to obtain a halting result as the problem is ill-formed: mapping a halting result of non-halting to the infinite
    recursion manifesting due to type mismatch is entirely artificial.

    /Flibble

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  • From Mr Flibble@21:1/5 to olcott on Sun May 11 17:15:54 2025
    On Sun, 11 May 2025 12:06:40 -0500, olcott wrote:

    On 5/11/2025 11:59 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 11:49:51 -0500, olcott wrote:

    On 5/11/2025 11:05 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 10:56:02 -0500, olcott wrote:

    On 5/11/2025 10:49 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 16:47:09 +0100, Richard Heathfield wrote:

    On 11/05/2025 16:34, Mr Flibble wrote:
    On Sun, 11 May 2025 16:25:14 +0100, Richard Heathfield wrote:

    For a question to be semantically incorrect, it takes more than >>>>>>>>> just you and your allies to be unhappy with it.

    For a question to be semantically correct, it takes more than
    just you and your allies to be happy with it.

    Indeed. It has to have meaning. It does. That meaning has to be
    understood by sufficiently intelligent people. It is.

    You don't like the question. I get that. I don't know /why/ you
    don't like it, because all your explanations to date have been
    complete expletive deleted. For a Usenet article to be
    semantically correct, it helps if your readers can understand what >>>>>>> the <exp. del.> you're talking about.

    What I get from your stand is that you agree with olcott that a
    'pathological' input halts... no, never halts... well, you can't >>>>>>> decide between you, but you're agreed that it's definitely
    decidable, right?

    Re-read the OP for my answer:

    Flibble’s Leap: Why Behavioral Divergence Implies a Type
    Distinction in the Halting Problem


    ===========================================================================================

    Summary -------
    Flibble argues that the Halting Problem's undecidability proof is
    built on a category (type) error: it assumes a program and its own >>>>>> representation (as a finite string) are interchangeable. This
    assumption fails under simulating deciders, revealing a type
    distinction through behavioral divergence. As such, all deciders
    must respect this boundary, and diagonalization becomes ill-formed. >>>>>> This reframing dissolves the paradox by making the Halting Problem >>>>>> itself an ill-posed question.

    1. Operational Evidence of Type Distinction
    -------------------------------------------
    - When a program (e.g., `DD()`) is passed to a simulating halt
    decider (`HHH`), it leads to infinite recursion.
    - This behavior differs from direct execution (e.g., a crash due to >>>>>> a stack overflow).

    The directly executed DD() simply halts because HHH has stopped the
    infinite recursion that it specifies on its second recursive call.

    That behaviour is due to a decision you have made, that I disagree
    with,
    the correct thing to do is to allow infinite recursion to manifest as
    stack overflow rather than return an artificial halting result.


    That fails to meet the spec of a termination analyzer.

    Nevertheless it is impossible to obtain a halting result as the problem
    is ill-formed: mapping a halting result of non-halting to the infinite
    recursion manifesting due to type mismatch is entirely artificial.

    /Flibble

    When a simulating termination analyzer examines the behavior that its
    input actually specifies and reports on this, then in the case of every conventional Halting Problem proof it is correct to reject this input as non-halting.

    But it would "halt" due to stack overflow if you let the simulation
    proceed.

    The truth is it neither halts nor doesn't halt as the question being asked
    is ill-formed.

    /Flibble

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  • From Mr Flibble@21:1/5 to Richard Heathfield on Sun May 11 17:33:51 2025
    On Sun, 11 May 2025 18:26:46 +0100, Richard Heathfield wrote:

    On 11/05/2025 18:15, Mr Flibble wrote:
    The truth is it neither halts nor doesn't halt as the question being
    asked is ill-formed.

    So it's stopped running, but it's started hopping?


    Your answer is bizarre, but it makes a lot more sense when we realise
    that you are desperately trying to avoid saying that it's undecidable.

    It is undecidable but not for the reason given by Turing.

    /Flibble

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  • From Mr Flibble@21:1/5 to Richard Heathfield on Sun May 11 17:26:36 2025
    On Sun, 11 May 2025 18:15:47 +0100, Richard Heathfield wrote:

    On 11/05/2025 17:59, Mr Flibble wrote:
    it is impossible to obtain a halting result


    That sure looks like a concession that it's impossible to devise an
    algorithm that will produce a halting result.

    Well done. We got you there in the end.

    No. The reason why it is impossible to obtain a halting result for
    pathological input is not the reason proposed by Turing (i.e. self-
    referential diagonalization), it is impossible to obtain a halting result
    for pathological input because the self-referential conflation of decider
    and input is a category error that prevents us from performing
    diagonalization.

    To usefully advance research in this area pathological input needs to be excluded from the set of programs that can be analysed by a decider.

    /Flibble

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  • From Mr Flibble@21:1/5 to Richard Damon on Sun May 11 21:42:35 2025
    On Sun, 11 May 2025 15:55:34 -0400, Richard Damon wrote:

    On 5/11/25 11:49 AM, Mr Flibble wrote:
    On Sun, 11 May 2025 16:47:09 +0100, Richard Heathfield wrote:

    On 11/05/2025 16:34, Mr Flibble wrote:
    On Sun, 11 May 2025 16:25:14 +0100, Richard Heathfield wrote:

    For a question to be semantically incorrect, it takes more than just >>>>> you and your allies to be unhappy with it.

    For a question to be semantically correct, it takes more than just
    you and your allies to be happy with it.

    Indeed. It has to have meaning. It does. That meaning has to be
    understood by sufficiently intelligent people. It is.

    You don't like the question. I get that. I don't know /why/ you don't
    like it, because all your explanations to date have been complete
    expletive deleted. For a Usenet article to be semantically correct, it
    helps if your readers can understand what the <exp. del.> you're
    talking about.

    What I get from your stand is that you agree with olcott that a
    'pathological' input halts... no, never halts... well, you can't
    decide between you, but you're agreed that it's definitely decidable,
    right?

    Re-read the OP for my answer:

    Which is full of errors as I have pointed out.

    Sorry mate but you have missed the boat as I have moved on: I am happy
    with my final solution; I glanced over all your responses in this thread
    and they are all invalid.

    In summary:
    * pathological input is undecidable but not for the reason given in the
    extant halting problem proofs;
    * pathological input should be removed from the set of programs that can
    be analysed by a decider for further research in this area to be useful
    rather than just a circle jerk.

    /Flibble

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