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.

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