• Re: No TM exists that can simulate all TM.

    From joes@21:1/5 to All on Fri Oct 25 17:15:51 2024
    Am Sat, 26 Oct 2024 01:12:00 +0800 schrieb wij:

    Proof: Simulating self is not possible (from all real programs, every
    one can verify).
    It is possible for a UTM to simulate itself simulating another program.

    This also implies UTM does not exist.
    Since they do, your premise or deduction must be wrong.

    Did Turing made a mistake?
    Probably not.

    --
    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 Richard Damon@21:1/5 to wij on Fri Oct 25 18:17:32 2024
    On 10/25/24 1:12 PM, wij wrote:
    Proof: Simulating self is not possible (from all real programs, every one can verify).

    This also implies UTM does not exist.

    Did Turing made a mistake? https://en.wikipedia.org/wiki/Universal_Turing_machine


    The key point you are missing is that if the UTM emulating a program
    like H^ (without the contrary nature at the end), so that we can get the infinite chain of UTM emulating that UTM emulating that UTM ..., it just
    ends up being a non-halting computation, and thus the non-halting
    emulation of that computation is exactly right.

    The problem is if you want it to be a UTM and also a decider, then you
    run into the problem.

    The UTM chain *IS* an infinite deep recursive simulation, which is just
    like the infinite-recursion, which is non-halting.

    When you change the UTM to be a decider (and thus no longer a UTM) it
    finds it can't know the answer for the behavior of the UTM it was
    previously.

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  • From Mikko@21:1/5 to wij on Sat Oct 26 10:56:55 2024
    On 2024-10-25 17:12:00 +0000, wij said:

    Proof: Simulating self is not possible (from all real programs, every
    one can verify).

    The starting point of that proof is false. An universal Turing machine
    that can simulate any Turing machine, including itself, can be and has
    been constructed.

    This also implies UTM does not exist.

    Existence of an UTM prooves otherwise.

    Did Turing made a mistake?

    Somebody did.

    --
    Mikko

    --- SoupGate-Win32 v1.05
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  • From Richard Damon@21:1/5 to wij on Sat Oct 26 11:35:45 2024
    On 10/26/24 10:08 AM, wij wrote:
    On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:
    On 10/25/24 1:12 PM, wij wrote:
    Proof: Simulating self is not possible (from all real programs, every one can verify).

    This also implies UTM does not exist.

    Did Turing made a mistake?
    https://en.wikipedia.org/wiki/Universal_Turing_machine


    The key point you are missing is that if the UTM emulating a program
    like H^ (without the contrary nature at the end), so that we can get the
    infinite chain of UTM emulating that UTM emulating that UTM ..., it just
    ends up being a non-halting computation, and thus the non-halting
    emulation of that computation is exactly right.

    The problem is if you want it to be a UTM and also a decider, then you
    run into the problem.

    The UTM chain *IS* an infinite deep recursive simulation, which is just
    like the infinite-recursion, which is non-halting.

    When you change the UTM to be a decider (and thus no longer a UTM) it
    finds it can't know the answer for the behavior of the UTM it was
    previously.

    Simulator::= A TM (utm) that performs the same function as its argument TM (f).
    IOW, utm(f)=f (or utm(f,arg)=f(arg))

    In case of self-simulation "utm(utm)" ... well, the argument utm has no argument
    (empty tape?) to define its behavior. What is the outer utm supposed to 'simulate'?

    How do you define 'simulator'? What exactly does UTM simulate?



    So, what does utm() do, one good definition is just halt.

    thus utm(utm) would emulate utm() which would just see it doesn't have
    an input and halt.

    UTMs are given a "description" of the Turing Machne and of its input,
    expressed in the "language" of the UTM.

    A simple (to understand,complicated to build) would be one where you
    give as an input listing of every possible state the machine could be in
    and every possible input character, and lists the resulting state,
    character to put on the tape, and tape motion, and the starting state,
    Then you put the contents of the tape that machine is to process with
    the current pointer of the starting point.

    The UTM then just applies the rules described in the first part, to the
    tape described in the second part, and when it gets to a state marked as
    a final state (perhaps one of the tape operations is "Halt", or states
    are marked as terminal) it stops and returns the results.

    This means that the UTM just "zimulates" the execution process of a
    Turing Machine, where one "step" takes the current state, and the
    contents of the tape at its current position, and updates the tape to
    the new value and move the current location of the tape, and updates the current state.

    The "proof" of the existance of a UTM was the proof that a Turing
    Machine could be programmed to do that set of transformations.

    --- SoupGate-Win32 v1.05
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  • From joes@21:1/5 to All on Sat Oct 26 16:18:34 2024
    Am Sat, 26 Oct 2024 22:08:23 +0800 schrieb wij:
    On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:
    On 10/25/24 1:12 PM, wij wrote:
    Proof: Simulating self is not possible (from all real programs, every
    one can verify).
    This also implies UTM does not exist.
    Did Turing made a mistake?

    The key point you are missing is that if the UTM emulating a program
    like H^ (without the contrary nature at the end), so that we can get
    the infinite chain of UTM emulating that UTM emulating that UTM ..., it
    just ends up being a non-halting computation, and thus the non-halting
    emulation of that computation is exactly right.
    The problem is if you want it to be a UTM and also a decider, then you
    run into the problem.
    The UTM chain *IS* an infinite deep recursive simulation, which is just
    like the infinite-recursion, which is non-halting.
    When you change the UTM to be a decider (and thus no longer a UTM) it
    finds it can't know the answer for the behavior of the UTM it was
    previously.

    Simulator::= A TM (utm) that performs the same function as its argument
    TM (f).
    IOW, utm(f)=f (or utm(f,arg)=f(arg))
    In case of self-simulation "utm(utm)" ... well, the argument utm has no argument (empty tape?) to define its behavior. What is the outer utm
    supposed to 'simulate'?
    How do you define 'simulator'? What exactly does UTM simulate?
    You also need an input for the simulated machine. I suppose you would
    want an infinite chain of UTMs simulating themselves simulating
    themselves (sic).

    --
    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
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From joes@21:1/5 to All on Sun Oct 27 09:17:42 2024
    Am Sun, 27 Oct 2024 17:05:52 +0800 schrieb wij:
    On Sat, 2024-10-26 at 11:35 -0400, Richard Damon wrote:
    On 10/26/24 10:08 AM, wij wrote:
    On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:
    On 10/25/24 1:12 PM, wij wrote:
    Proof: Simulating self is not possible (from all real programs,
    every one can verify).
    This also implies UTM does not exist.
    Did Turing made a mistake?

    The key point you are missing is that if the UTM emulating a
    program like H^ (without the contrary nature at the end), so that
    we can get the infinite chain of UTM emulating that UTM emulating
    that UTM ..., it just ends up being a non-halting computation, and
    thus the non-halting emulation of that computation is exactly
    right.
    The problem is if you want it to be a UTM and also a decider, then
    you run into the problem.
    The UTM chain *IS* an infinite deep recursive simulation, which is
    just like the infinite-recursion, which is non-halting.
    When you change the UTM to be a decider (and thus no longer a UTM)
    it finds it can't know the answer for the behavior of the UTM it
    was previously.

    Simulator::= A TM (utm) that performs the same function as its
    argument TM (f).
                  IOW, utm(f)=f  (or utm(f,arg)=f(arg))
    In case of self-simulation "utm(utm)" ... well, the argument utm has
    no argument (empty tape?) to define its behavior. What is the outer
    utm supposed to 'simulate'?
    How do you define 'simulator'? What exactly does UTM simulate?

    So, what does utm() do, one good definition is just halt.
    thus utm(utm) would emulate utm() which would just see it doesn't have
    an input and halt.
    UTMs are given a "description" of the Turing Machne and of its input,
    expressed in the "language" of the UTM.
    A simple (to understand,complicated to build) would be one where you
    give as an input listing of every possible state the machine could be
    in and every possible input character, and lists the resulting state,
    character to put on the tape, and tape motion, and the starting state,
    Then you put the contents of the tape that machine is to process with
    the current pointer of the starting point.
    The UTM then just applies the rules described in the first part, to the
    tape described in the second part, and when it gets to a state marked
    as a final state (perhaps one of the tape operations is "Halt", or
    states are marked as terminal) it stops and returns the results.
    This means that the UTM just "zimulates" the execution process of a
    Turing Machine, where one "step" takes the current state, and the
    contents of the tape at its current position, and updates the tape to
    the new value and move the current location of the tape, and updates
    the current state.
    The "proof" of the existance of a UTM was the proof that a Turing
    Machine could be programmed to do that set of transformations.

    That's right. You need to REPROGRAM. You need to modify the transition function and the symbols, and the tape contents.
    Therefore, "No real UTM exists". "An Univeral TM" is a false idea.
    lolwut? The transition function is not modified, that would make it
    a different machine. The tape of course needs to be modified.

    --
    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
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Richard Damon@21:1/5 to wij on Sun Oct 27 07:38:44 2024
    On 10/27/24 5:05 AM, wij wrote:
    On Sat, 2024-10-26 at 11:35 -0400, Richard Damon wrote:
    On 10/26/24 10:08 AM, wij wrote:
    On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:
    On 10/25/24 1:12 PM, wij wrote:
    Proof: Simulating self is not possible (from all real programs, every one can verify).

    This also implies UTM does not exist.

    Did Turing made a mistake?
    https://en.wikipedia.org/wiki/Universal_Turing_machine


    The key point you are missing is that if the UTM emulating a program
    like H^ (without the contrary nature at the end), so that we can get the >>>> infinite chain of UTM emulating that UTM emulating that UTM ..., it just >>>> ends up being a non-halting computation, and thus the non-halting
    emulation of that computation is exactly right.

    The problem is if you want it to be a UTM and also a decider, then you >>>> run into the problem.

    The UTM chain *IS* an infinite deep recursive simulation, which is just >>>> like the infinite-recursion, which is non-halting.

    When you change the UTM to be a decider (and thus no longer a UTM) it
    finds it can't know the answer for the behavior of the UTM it was
    previously.

    Simulator::= A TM (utm) that performs the same function as its argument TM (f).
                  IOW, utm(f)=f  (or utm(f,arg)=f(arg))

    In case of self-simulation "utm(utm)" ... well, the argument utm has no argument
    (empty tape?) to define its behavior. What is the outer utm supposed to 'simulate'?

    How do you define 'simulator'? What exactly does UTM simulate?



    So, what does utm() do, one good definition is just halt.

    thus utm(utm) would emulate utm() which would just see it doesn't have
    an input and halt.

    UTMs are given a "description" of the Turing Machne and of its input,
    expressed in the "language" of the UTM.

    A simple (to understand,complicated to build) would be one where you
    give as an input listing of every possible state the machine could be in
    and every possible input character, and lists the resulting state,
    character to put on the tape, and tape motion, and the starting state,
    Then you put the contents of the tape that machine is to process with
    the current pointer of the starting point.

    The UTM then just applies the rules described in the first part, to the
    tape described in the second part, and when it gets to a state marked as
    a final state (perhaps one of the tape operations is "Halt", or states
    are marked as terminal) it stops and returns the results.

    This means that the UTM just "zimulates" the execution process of a
    Turing Machine, where one "step" takes the current state, and the
    contents of the tape at its current position, and updates the tape to
    the new value and move the current location of the tape, and updates the
    current state.

    The "proof" of the existance of a UTM was the proof that a Turing
    Machine could be programmed to do that set of transformations.


    That's right. You need to REPROGRAM. You need to modify the transition function and
    the symbols, and the tape contents.
    Therefore, "No real UTM exists". "An Univeral TM" is a false idea.


    No, the PROGRAM of the Turing Machine that is a UTM, is the single
    program that interprests those codes and transforms them. It can be one
    single program. The one slight, but solvable, difficulty is that we
    don't know how many states or characters are used by the target machine,
    so we encode those in the description tape with a method to encode
    arbitrary precision numbers, a solved problem.

    Note, one good example that is very close to the idealized UTM (except
    for having only a finite memory, not an infinte tape) is a "modern"
    single core CPU chip. We can encode any program we want, and put it into
    the memory of the chip (which is its version of the "tape") and the CPU
    will run that progtram, and we don't need to change the CPU for each
    different program.

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