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From: "Fred. Zwarts" <F.Zwarts@HetNet.nl>
Newsgroups: comp.theory
Subject: Re: DDD specifies recursive emulation to HHH and halting to HHH1
Date: Thu, 27 Mar 2025 20:56:40 +0100
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Op 27.mrt.2025 om 18:50 schreef olcott:
> On 3/27/2025 2:18 AM, Fred. Zwarts wrote:
>> Op 27.mrt.2025 om 04:09 schreef olcott:
>>> On 3/26/2025 8:22 PM, Richard Damon wrote:
>>>
>>> _DDD()
>>> [00002172] 55         push ebp      ; housekeeping
>>> [00002173] 8bec       mov  ebp,esp  ; housekeeping
>>> [00002175] 6872210000 push 00002172 ; push DDD
>>> [0000217a] e853f4ffff call 000015d2 ; call HHH(DDD)
>>> [0000217f] 83c404     add  esp,+04
>>> [00002182] 5d         pop  ebp
>>> [00002183] c3         ret
>>> Size in bytes:(0018) [00002183]
>>>
>>>> Non-Halting is that the machine won't reach its final staste even if 
>>>> an unbounded number of steps are emulated. Since HHH doesn't do 
>>>> that, it isn't showing non-halting.
>>>>
>>>
>>> DDD emulated by any HHH will never reach its final state
>>> in an unbounded number of steps.
>>>
>>> DDD emulated by HHH1 reaches its final state in a finite
>>> number of steps.
>>>
>> It is not very interesting to know whether a simulator reports that it 
>> is unable to reach the end of the simulation of a program that halts 
>> in direct execution.
> 
> That IS NOT what HHH is reporting.
> HHH correctly rejects DDD because DDD correctly
> emulated by HHH cannot possibly reach its own
> final halt state.

Yes, that is the same in other words as rejecting because it could not 
correctly simulate the input up to its end. An end that exists as proven 
by direct execution and world-class simulators.
It is not very interesting to know whether a simulator reports that it 
is unable to reach the end of the simulation of a program that halts in 
direct execution (and therefore rejects the input).
It is interesting to know:
'Is there an algorithm that can determine for all possible inputs 
whether the input specifies a program that (according to the semantics 
of the machine language) halts when directly executed?'
This question seems undecidable for Olcott.



> 
>> It is interesting to know:
>> 'Is there an algorithm that can determine for all possible inputs 
>> whether the input specifies a program that (according to the semantics 
>> of the machine language) halts when directly executed?'
> 
> It is the halts while directly executed that is impossible
> for all inputs. No TM can ever report on the behavior of
> the direct execution of any other TM.
> 
I assume that is a 'no' to the question. Correct?