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