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.

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