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From: Richard Damon <richard@damon-family.org>
Newsgroups: comp.theory
Subject: Re: Incorrect requirements --- Computing the mapping from the input
 to HHH(DD)
Date: Fri, 9 May 2025 13:00:18 -0400
Organization: i2pn2 (i2pn.org)
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On 5/9/25 11:48 AM, olcott wrote:
> On 5/9/2025 3:47 AM, Fred. Zwarts wrote:
>> Op 09.mei.2025 om 04:23 schreef Keith Thompson:
>>> 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?
>>>
>>
>> What you are missing is that the next step of olcott is to say that 
>> when he uses the 'exact same HHH, with only some extra code to abort 
>> the simulation', it is still an infinite recursion. He does not 
>> understand that adding the abort code makes the behaviour 
>> fundamentally different. 
> 
> When 1 or more statements of DDD are correctly simulated
> by HHH this correctly simulated DDD cannot possibly reach
> its own "return statement" final halt state.


But HHH can not correctly emulate this input (the code of just DDD) past 
the call instruction and remain a pure function, as it hasn't been given 
that code.

If HHH doesn't need to be a pure function, then I have shown an HHH that 
does what you say can't be done.

> 
> Reaching the final halt state is the only correct
> measure of halting. Thus the finite string input
> to HHH(DDD) specifies a non-halting sequence of
> configurations.

Right, but that needs a full program as the input so it HAS behavior, 
and non-halting is only implied if an actual correct emulation (that 
doesn't abort) will never reach such a statement even after processing 
an unbounded number of steps.

Stopping before then just shows "Not Yet Halted".

> 
>> It is difficult for him to understand, because he refuses to use 
>> different names for the different versions of HHH, because he dreams 
>> that they are al exactly the same (except for small changes).
> 
>