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.

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