Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.theory > #118658
| From | Mikko <mikko.levanto@iki.fi> |
|---|---|
| Newsgroups | comp.theory |
| Subject | Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED |
| Date | 2025-05-12 10:45 +0300 |
| Organization | - |
| Message-ID | <vvs8uk$vu1r$1@dont-email.me> (permalink) |
| References | <vvmudo$3dk35$1@dont-email.me> <vvnqes$3in62$5@dont-email.me> <vvppls$4155$1@dont-email.me> <vvqhoh$gldn$7@dont-email.me> |
On 2025-05-11 16:03:29 +0000, olcott said:
> On 5/11/2025 4:12 AM, Mikko wrote:
>> On 2025-05-10 15:13:32 +0000, olcott said:
>>
>>> On 5/10/2025 2:15 AM, Mikko wrote:
>>>> On 2025-05-09 03:01:40 +0000, olcott said:
>>>>
>>>>> On 5/8/2025 9:23 PM, Keith Thompson wrote:
>>>>>> Richard Damon <richard@damon-family.org> writes:
>>>>>>> On 5/8/25 7:53 PM, olcott wrote:
>>>>>> [...]
>>>>>>>> void DDD()
>>>>>>>> {
>>>>>>>> Â HHH(DDD);
>>>>>>>> Â return;
>>>>>>>> }
>>>>>>>> We don't need to look at any of my code for me
>>>>>>>> to totally prove my point. For example when
>>>>>>>> the above DDD is correctly simulated by HHH
>>>>>>>> this simulated DDD cannot possibly reach its own
>>>>>>>> "return" instruction.
>>>>>>>
>>>>>>> And thus not correctly simulatd.
>>>>>>>
>>>>>>> Sorry, there is no "OS Exemption" to correct simulaiton;.
>>>>>>
>>>>>> Perhaps I've missed something. I don't see anything in the above that
>>>>>> implies that HHH does not correctly simulate DDD. Richard, you've read
>>>>>> far more of olcott's posts than I have, so perhaps you can clarify.
>>>>>>
>>>>>> If we assume that HHH correctly simulates DDD, then the above code is
>>>>>> equivalent to:
>>>>>>
>>>>>> void DDD()
>>>>>> {
>>>>>> DDD();
>>>>>> return;
>>>>>> }
>>>>>>
>>>>>> which is a trivial case of infinite recursion. As far as I can tell,
>>>>>> assuming that DDD() is actually called at some point, neither the
>>>>>> outer execution of DDD nor the nested (simulated) execution of DDD
>>>>>> can reach the return statement. Infinite recursion might either
>>>>>> cause a stack overflow and a probable program crash, or an unending
>>>>>> loop if the compiler implements tail call optimization.
>>>>>>
>>>>>> I see no contradiction, just an uninteresting case of infinite
>>>>>> recursion, something that's well understood by anyone with a
>>>>>> reasonable level of programming experience. (And it has nothing to
>>>>>> do with the halting problem as far as I can tell, though of course
>>>>>> olcott has discussed the halting problem elsewhere.)
>>>>>>
>>>>>> Richard, what am I missing?
>>>>>>
>>>>> *****
>>>>> Now you are seeing what I was talking about.
>>>>> Now you are seeing why I needed to cross post
>>>>> to comp.lang.c
>>>>
>>>> What were you told in comp.lang.c that you were not told in comp.theory?
>>>
>>> void DDD()
>>> {
>>> HHH(DDD);
>>> return;
>>> }
>>>
>>> People quickly realize that when DDD is correctly
>>> simulated by HHH that DDD cannot possibly reach
>>> its "return" statement (final halt state).
>>>
>>> Once you know this then you can see that the
>>> same thing applies to DD.
>>>
>>> int DD()
>>> {
>>> int Halt_Status = HHH(DD);
>>> if (Halt_Status)
>>> HERE: goto HERE;
>>> return Halt_Status;
>>> }
>>>
>>> Once you know this then you know that the halting
>>> problem's otherwise "impossible" input is non-halting.
>>>
>>> Once you know this then you know that the halting
>>> problem proof has been correctly refuted.
>>
>> You are lying again. Nothing above was told you in comp.lang.c.
>
> On 5/8/2025 8:30 PM, Keith Thompson wrote:
> > Assuming that HHH(DDD) "correctly simulates" DDD, and assuming it
> > does nothing else, your code would be equivalent to this:
> >
> > void DDD(void) {
> > DDD();
> > return;
> > }
> >
> > Then the return statement (which is unnecessary anyway) will never be
> > reached. In practice, the program will likely crash due to a stack
> > overflow, unless the compiler implements tail-call optimization, in
> > which case the program might just run forever -- which also means the
> > unnecessary return statement will never be reached.
> >
What he says is true. However, the assumptions that HHH does a correct
simulation and that it does nothing else are not.
--
Mikko
Back to comp.theory | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Re: Why I need to cross-post to comp.lang.c Mikko <mikko.levanto@iki.fi> - 2025-05-10 10:15 +0300
Re: Why I need to cross-post to comp.lang.c Richard Heathfield <rjh@cpax.org.uk> - 2025-05-10 11:10 +0100
Re: Why I need to cross-post to comp.lang.c Richard Damon <richard@damon-family.org> - 2025-05-10 08:30 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED olcott <polcott333@gmail.com> - 2025-05-10 10:13 -0500
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED wij <wyniijj5@gmail.com> - 2025-05-10 23:39 +0800
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED "Fred. Zwarts" <F.Zwarts@HetNet.nl> - 2025-05-10 17:47 +0200
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Richard Damon <richard@damon-family.org> - 2025-05-10 14:24 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Mikko <mikko.levanto@iki.fi> - 2025-05-11 12:12 +0300
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED olcott <polcott333@gmail.com> - 2025-05-11 11:03 -0500
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED dbush <dbush.mobile@gmail.com> - 2025-05-11 12:05 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-11 15:19 -0700
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Richard Damon <richard@damon-family.org> - 2025-05-11 16:09 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Mikko <mikko.levanto@iki.fi> - 2025-05-12 10:45 +0300
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED olcott <polcott333@gmail.com> - 2025-05-12 09:47 -0500
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED dbush <dbush.mobile@gmail.com> - 2025-05-12 10:53 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED olcott <polcott333@gmail.com> - 2025-05-12 11:24 -0500
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED dbush <dbush.mobile@gmail.com> - 2025-05-12 12:42 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED olcott <polcott333@gmail.com> - 2025-05-12 11:59 -0500
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED dbush <dbush.mobile@gmail.com> - 2025-05-12 13:08 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED olcott <polcott333@gmail.com> - 2025-05-12 12:19 -0500
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED dbush <dbush.mobile@gmail.com> - 2025-05-12 13:31 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Mikko <mikko.levanto@iki.fi> - 2025-05-13 12:13 +0300
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Richard Damon <richard@damon-family.org> - 2025-05-12 22:18 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Richard Damon <richard@damon-family.org> - 2025-05-12 22:15 -0400
Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED Mikko <mikko.levanto@iki.fi> - 2025-05-13 12:10 +0300
csiph-web