On 10/21/2022 8:59 AM, Mr Flibble wrote:
> On Thu, 20 Oct 2022 16:44:31 -0500
> olcott <polcott2@gmail.com> wrote:
>
>> On 10/20/2022 4:29 PM, Mr Flibble wrote:
>>> On Thu, 20 Oct 2022 14:58:01 -0500
>>> olcott <polcott2@gmail.com> wrote:
>>>
>>>> On 10/20/2022 2:28 PM, Fred. Zwarts wrote:
>>>>> Op 19.okt..2022 om 19:28 schreef olcott:
>>>>>> On 10/19/2022 12:13 PM, Fred. Zwarts wrote:
>>>>>>> Op 19.okt..2022 om 19:01 schreef olcott:
>>>>>>>> On 10/19/2022 11:43 AM, Fred. Zwarts wrote:
>>>>>>>>> Op 18.okt..2022 om 21:46 schreef olcott:
>>>>>>>>>> On 10/18/2022 2:23 PM, Fred. Zwarts wrote:
>>>>>>>>>>> Op 18.okt..2022 om 17:02 schreef olcott:
>>>>>>>>>>>> On 10/18/2022 3:17 AM, Fred. Zwarts wrote:
>>>>>>>>>>>>> Op 17.okt..2022 om 23:22 schreef olcott:
>>>>>>>>>>>>>> On 10/17/2022 1:44 PM, Fred. Zwarts wrote:
>>>>>>>>>>>>>>> Op 17.okt..2022 om 16:29 schreef olcott:
>>>>>>>>>>>>>>>> On 10/17/2022 4:30 AM, Fred. Zwarts wrote:
>>>>>>>>>>>>>>>>> I have been following the discussions about Halt
>>>>>>>>>>>>>>>>> deciders with interest. As a retired software designer
>>>>>>>>>>>>>>>>> and developer, I have a lot of practical experience,
>>>>>>>>>>>>>>>>> but not much theoretical education, although the
>>>>>>>>>>>>>>>>> theoretical background is very interesting. I learned
>>>>>>>>>>>>>>>>> a lot. I would like to verify that I understand it
>>>>>>>>>>>>>>>>> correctly. Could you point out any errors in the
>>>>>>>>>>>>>>>>> summary below?
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> 1) (Definition of halt) A program X with input Y is
>>>>>>>>>>>>>>>>> said to halt if it reaches its end condition after a
>>>>>>>>>>>>>>>>> finite number of steps. It does not halt if it
>>>>>>>>>>>>>>>>> continues to execute infinitely.
>>>>>>>>>>>>>>>>> (So, X(Y) either halts, or it does not halt.)
>>>>>>>>>>>>>>>>> (It is irrelevant whether the end condition is reached
>>>>>>>>>>>>>>>>> in the 'normal' way, or by other means, e.g. an
>>>>>>>>>>>>>>>>> unhandled 'exception'.)
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> 2) (Definition of halt decider) A halt decider H is a
>>>>>>>>>>>>>>>>> program that, given a program X with input Y decides,
>>>>>>>>>>>>>>>>> after a finite number of steps, whether X(Y) halts or
>>>>>>>>>>>>>>>>> not. (H(X,Y) itself must halt after a finite number of
>>>>>>>>>>>>>>>>> steps. It must return either 1 if X(Y) halts, or 0 if
>>>>>>>>>>>>>>>>> X(Y) does not halt, where 1 and 0 are a convention,
>>>>>>>>>>>>>>>>> which could also be two other arbitrary values.)
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> *Professor Sipser has agreed to these verbatim words*
>>>>>>>>>>>>>>>> (and no more)
>>>>>>>>>>>>>>>> If simulating halt decider H correctly simulates its
>>>>>>>>>>>>>>>> input D until H
>>>>>>>>>>>>>>>> correctly determines that its simulated D would never
>>>>>>>>>>>>>>>> stop running
>>>>>>>>>>>>>>>> unless aborted then H can abort its simulation of D and
>>>>>>>>>>>>>>>> correctly report
>>>>>>>>>>>>>>>> that D specifies a non-halting sequence of
>>>>>>>>>>>>>>>> configurations.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> An alternative definition for a halt decider approved
>>>>>>>>>>>>>>>> by MIT Professor Michael Sipser (author of the best
>>>>>>>>>>>>>>>> selling book on the theory of computation)
>>>>>>>>>>>>>>>> https://www.amazon.com/Introduction-Theory-Computation-Sipser/dp/8131525295
>>>>>>>>>>>>>>>> is shown above and paraphrased below:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Would D correctly simulated by H ever stop running if
>>>>>>>>>>>>>>>> not aborted?
>>>>>>>>>>>>>>>> Is proven on page 3 of this paper to be "no" thus
>>>>>>>>>>>>>>>> perfectly meeting the Sipser approved criteria shown
>>>>>>>>>>>>>>>> above.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> *Rebutting the Sipser Halting Problem Proof*
>>>>>>>>>>>>>>>> https://www.researchgate.net/publication/364302709_Rebutting_the_Sipser_Halting_Problem_Proof
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> It is not clear to me what you want to say and why you
>>>>>>>>>>>>>>> left out my other points from the quote. You quote only
>>>>>>>>>>>>>>> the definitions. You left out the points that follow
>>>>>>>>>>>>>>> from the definitions. What does that mean. Don't you
>>>>>>>>>>>>>>> agree with the definitions, or is something wrong with
>>>>>>>>>>>>>>> the other points?
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> *Professor Sipser has agreed to these verbatim words*
>>>>>>>>>>>>>> (and no more)
>>>>>>>>>>>>>> If simulating halt decider H correctly simulates its
>>>>>>>>>>>>>> input D until H
>>>>>>>>>>>>>> correctly determines that its simulated D would never
>>>>>>>>>>>>>> stop running
>>>>>>>>>>>>>> unless aborted then H can abort its simulation of D and
>>>>>>>>>>>>>> correctly report
>>>>>>>>>>>>>> that D specifies a non-halting sequence of
>>>>>>>>>>>>>> configurations.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Because the above seems to agree with my definition of a
>>>>>>>>>>>>>> simulating halt decider other definitions that do not
>>>>>>>>>>>>>> apply to simulating halt deciders are irrelevant.
>>>>>>>>>>>>>
>>>>>>>>>>>>> I was not talking about simulating halt deciders, but
>>>>>>>>>>>>> about halt deciders. Since we seem to agree that they are
>>>>>>>>>>>>> not the same, I have to conclude that your contribution is
>>>>>>>>>>>>> irrelevant.
>>>>>>>>>>>>
>>>>>>>>>>>> That is the same as saying that airplanes do not fly
>>>>>>>>>>>> because cars do not fly and we were talking about cars.
>>>>>>>>>>>
>>>>>>>>>>> If we are talking about cars, it is irrelevant to change the
>>>>>>>>>>> subject to airplanes.
>>>>>>>>>>> But if you think your car is an airplane, it is dangerous to
>>>>>>>>>>> try to fly with it.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> *Professor Sipser has agreed to these verbatim words* (and no
>>>>>>>>>> more) If simulating halt decider *H correctly simulates its
>>>>>>>>>> input D until H*
>>>>>>>>>> *correctly determines that its simulated D would never stop
>>>>>>>>>> running* *unless aborted* then H can abort its simulation of
>>>>>>>>>> D and correctly report that D specifies a non-halting
>>>>>>>>>> sequence of configurations.
>>>>>>>>>>
>>>>>>>>>> Seems to be saying that a simulating halt decider does
>>>>>>>>>> correctly determine the halt status of its input.
>>>>>>>>>>
>>>>>>>>>> The only requirement for a halt decider is that it does
>>>>>>>>>> correctly determine the halt status of its inputs.
>>>>>>>>>
>>>>>>>>> I started this thread with a question about Halt Deciders. I
>>>>>>>>> included a definition (see above). Why do you keep changing
>>>>>>>>> the subject to things with other definitions? Cars, airplanes,
>>>>>>>>> simulating halt deciders, boats, automobiles? Please, stay at
>>>>>>>>> the subject.
>>>>>>>>
>>>>>>>> The above quote seems to say that a simulating halt decider
>>>>>>>> does correctly determine the halt status of the input that it
>>>>>>>> simulates.
>>>>>>>>
>>>>>>>> Professor Sipser is the author of the best selling book on the
>>>>>>>> theory of computation would seem to have the knowledge required
>>>>>>>> to approve alternative definitions for halt deciders.
>>>>>>>>
>>>>>>>> https://www.amazon.com/Introduction-Theory-Computation-Sipser/dp/8131525295
>>>>>>>>
>>>>>>>> Only the notion of a simulating halt decider defeats the
>>>>>>>> conventional HP proofs. To insist on definitions that cannot
>>>>>>>> defeat these proofs seems a little silly.
>>>>>>>>
>>>>>>>
>>>>>>> So, your contribution is irrelevant, because you want to change
>>>>>>> definitions and you cannot show any error in the 9 points I was
>>>>>>> asking about.
>>>>>>> Don't change the subject, please.
>>>>>>
>>>>>> In computability theory, the halting problem is the problem of
>>>>>> determining, from a description of an arbitrary computer program
>>>>>> and an input, whether the program will finish running, or
>>>>>> continue to run forever. Alan Turing proved in 1936 that a
>>>>>> general algorithm to solve the halting problem for all possible
>>>>>> program-input pairs cannot exist.
>>>>>>
>>>>>> For any program H that might determine if programs halt, a
>>>>>> "pathological" program D, called with some input, can pass its
>>>>>> own source and its input to H and then specifically do the
>>>>>> opposite of what H predicts D will do. No H can exist that
>>>>>> handles this case. https://en.wikipedia.org/wiki/Halting_problem
>>>>>>
>>>>>> H(D,D) correctly simulates its input D until H correctly
>>>>>> determines that its simulated D would never stop running unless
>>>>>> aborted thus exactly matching the Wikipedia definition of an H
>>>>>> can that handles this case.
>>>>>>
>>>>>
>>>>> Your H returns 0, but D halts. Again you changed the subject.
>>>>
>>>> You continue to look for a black dog in the kitchen by looking for
>>>> a white cat in the living room because you only understand these
>>>> things on the basis of learned-by-rote.
>>>>
>>>> That the behavior of the input D correctly simulated by H is
>>>> validated as the correct basis for a halt status decision prevents
>>>> anyone from correctly disagreeing with this basis within this
>>>> validated basis.
>>>
>>> If D(D) halts then H(D,D) should return a decision of halts (1).
>>>
>>> /Flibble
>>>
>>
>> One would think so until one looked at all of the details.
>
> If D(D) halts then H(D,D) should return a decision of halts (1).
>
> /Flibble
>

One would think so until one looked at all of the details.

--
Copyright 2022 Pete Olcott "Talent hits a target no one else can hit;
Genius hits a target no one else can see." Arthur Schopenhauer