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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: Why I need to cross-post to comp.lang.c --- CORRECTLY REFUTED
Date: Sun, 11 May 2025 12:12:28 +0300
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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()
>>>>>> {
>>>>>>   HHH(DDD);
>>>>>>   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.

-- 
Mikko