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From: "Fred. Zwarts" <F.Zwarts@HetNet.nl>
Newsgroups: comp.theory,sci.logic
Subject: Re: DDD correctly emulated by HHH is correctly rejected as
 non-halting.
Date: Thu, 11 Jul 2024 09:32:22 +0200
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Op 10.jul.2024 om 20:32 schreef olcott:
> On 7/10/2024 1:12 PM, Alan Mackenzie wrote:
>> [ Followup-To: set ]
>>
>> In comp.theory Fred. Zwarts <F.Zwarts@hetnet.nl> wrote:
>>
>> [ .... ]
>>
>>> Proving that the simulation is incorrect. Because a correct simulation
>>> would not abort a halting program halfway its simulation.
>>
>> Just for clarity, a correct simulation wouldn't abort a non-halting
>> program either, would it?  Or have I misunderstood this correctness?
>>
>> [ .... ]
>>
> 
> Welcome back.
> I stipulate that I am referring to 1 to ∞ steps of correct
> emulation according to the semantics of the x86 language.
> 
> This means that when HHH does correctly emulate 1 step
> that *it is a correct emulation* of this 1 step, thus
> making everyone that disagrees disagree with a tautology
> making them look foolish.

And nobody disagrees with that. So, *you* look foolish. The disagreement 
is that you think that simulating only 1 step for a program that needs N 
steps is correct, whereas we know that a correct simulation needs N
steps. It is a finite recursion as in:

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

It seems that you do not understand the semantics of the x86 language, 
which requires the simulation of all N steps.

> 
> We stipulate that the only measure of a correct emulation
> is the semantics of the x86 programming language. 

So, use it. Simulate all N steps.
We know that an aborting program does halt, so the number of steps to 
simulate is finite.
Your problem is that HHH cannot possibly simulate itself correctly up to 
the end. You need another simulator for that.

> By this
> measure when 1 to ∞ steps of DDD are correctly emulated
> by each pure function x86 emulator HHH (of the infinite
> set of every HHH that can possibly exist) then DDD cannot
> possibly reach past its own machine address of 0000216b
> and halt.

Yes. This proves that HHH cannot possibly simulate itself correctly up 
to the end.

> 
> _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]
>