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From: "Fred. Zwarts" <F.Zwarts@HetNet.nl>
Newsgroups: comp.theory
Subject: Re: Hypothetical possibilities
Date: Sun, 21 Jul 2024 18:42:26 +0200
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Op 21.jul.2024 om 16:25 schreef olcott:
> On 7/21/2024 5:25 AM, Fred. Zwarts wrote:
>> Op 20.jul.2024 om 22:08 schreef olcott:
>>> On 7/20/2024 3:03 PM, Alan Mackenzie wrote:
>>>> [ Followup-To: set ]
>>>>
>>>> In comp.theory Fred. Zwarts <F.Zwarts@hetnet.nl> wrote:
>>>>
>>>> [ .... ]
>>>>
>>>>> Olcott could not point to an error, but prefers to ignore it. So, I 
>>>>> will
>>>>> repeat it, until either an error is found, or olcott admits that HHH
>>>>> cannot possibly simulate itself correctly.
>>>>
>>>> This has the disadvantage of making your posts boring to read.  All but
>>>> one poster on this newsgroup KNOW that Olcott is wrong, here.
>>>>
>>>> Continually repeating your argument won't get him to admit he's wrong.
>>>> Richard has been trying that for much longer than you have, with the
>>>> same lack of success.  Olcott's lack of capacity for abstract 
>>>> reasoning,
>>>> combined with his ignorance, combined with his arrogance, prevent him
>>>> learning at all.
>>>>
>>>> May I suggest that you reconsider your strategy of endless repetition?
>>>>
>>>> Thanks!
>>>>
>>>
>>> So you are going to stupidly disagree with this?
>>>
>>> void DDD()
>>> {
>>>    HHH(DDD);
>>>    return;
>>> }
>>>
>>> It *is* a fact that no DDD correctly simulated by any
>>> pure function HHH ever reaches its own return instruction.
>>
>> Which proves that these simulations are incorrect.
>>
> 
> _DDD()
> [00002163] 55         push ebp      ; housekeeping
> [00002164] 8bec       mov ebp,esp   ; housekeeping
> [00002166] 6863210000 push 00002163 ; push DDD
> [0000216b] e853f4ffff call 000015c3 ; call HHH(DDD)
> [00002170] 83c404     add esp,+04
> [00002173] 5d         pop ebp
> [00002174] c3         ret
> Size in bytes:(0018) [00002174]
> 
> *You don't get to be the judge of this*

Neither are *you*.

> As long as the x86 machine language instructions of DDD
> are emulated by HHH according to the semantic meaning
> of these instructions then the emulation is correct and
> anyone that disagrees is disagreeing with a tautology.

But if some x86 instructions are skipped, then it is dishonest to say 
that it is a correct simulation. If the last cycle of HHH, after which 
it would halt, is skipped by the simulation, then the simulation is 
incorrect.
It is dishonest to deny that skipping instructions is correct according 
to the semantics of the x86 language.

> 
> This correct emulation must take into account the fact
> that DDD is calling its own emulator: HHH(DDD) in recursive
> emulation.
> 

And since HHH cannot possibly simulate itself correctly, the simulation 
of DDD is incorrect.


DDD is a misleading and unneeded complication. It is easy to eliminate DDD:

        int main() {
          return HHH(main);
        }

This has the same problem. This proves that the problem is not in DDD, 
but in HHH, which halts when it aborts the simulation, but it decides 
that the simulation of itself does not halt.
It shows that HHH cannot possibly simulate itself correctly.

HHH is simply unable to decide about finite recursions.

void Finite_Recursion (int N) {
   if (N > 0) Finite_Recursion (N - 1);
}

It decides after N recursions that there is an infinite recursion, which 
is incorrect.

Olcott's HHH is programmed to abort the simulation after N cycles of 
recursive simulations. Therefore, it is incorrect to abort the 
simulation of HHH when the simulated HHH has performed only N-1 cycles, 
because that changes the behaviour of HHH.
Since the simulated HHH always runs one cycle behind the simulating HHH, 
it is clear that HHH can never simulate enough cycles for a correct 
simulation, as is required by the x86 language.
Therefore, the simulation is incorrect according to the criteria olcott 
stipulated.
The conclusion is simple:
HHH cannot possibly simulate itself correctly.

No matter how much olcott wants it to be correct, or how many times 
olcott repeats that it is correct, it does not change the fact that such 
a simulation is incorrect, because it is unable to reach the end.
Olcott's own claim that the simulated HHH does not reach its end 
confirms it. The trace he has shown also proves that HHH cannot reach 
the end of its own simulation. So, his own claims prove that it is true 
that HHH cannot possibly simulate itself up to the end, which makes the 
simulation incorrect.

Sipser would agree that this incorrect simulation cannot be used to 
detect a non-halting behaviour.

Olcott does not know how to point to an error in this explanation, but 
prefers to ignore it. He even consistently removes it from the 
citations. So, I will repeat it, until either an error is found, or 
olcott admits that HHH cannot possibly simulate itself correctly.