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From: olcott <polcott333@gmail.com>
Newsgroups: sci.logic,comp.theory
Subject: Re: Every D correctly simulated by H never reaches its final state
 and halts
Date: Fri, 17 May 2024 12:46:29 -0500
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On 5/17/2024 11:00 AM, Mikko wrote:
> On 2024-05-17 15:30:01 +0000, olcott said:
> 
>> On 5/17/2024 2:25 AM, Fred. Zwarts wrote:
>>> Op 17.mei.2024 om 03:15 schreef olcott:
>>>> The following is self-evidently true on the basis of the
>>>> semantics of the C programming language.
>>>>
>>>> typedef int (*ptr)();  // ptr is pointer to int function
>>>> 00 int H(ptr x, ptr x);
>>>> 01 int D(ptr x)
>>>> 02 {
>>>> 03   int Halt_Status = H(x, x);
>>>> 04   if (Halt_Status)
>>>> 05     HERE: goto HERE;
>>>> 06   return Halt_Status;
>>>> 07 }
>>>> 08
>>>> 09 int main()
>>>> 10 {
>>>> 11   H(D,D);
>>>> 12   return 0;
>>>> 13 }
>>>>
>>>> In the above case a simulator is an x86 emulator that correctly
>>>> emulates at least one of the x86 instructions of D in the order
>>>> specified by the x86 instructions of D.
>>>>
>>>> This may include correctly emulating the x86 instructions of H
>>>> in the order specified by the x86 instructions of H thus calling
>>>> H(D,D) in recursive simulation.
>>>>
>>>> Any H/D pair matching the above template where
>>>> D(D) is simulated by the same H(D,D) that it calls
>>>> cannot possibly reach its own line 06 and halt.
>>>>
>>>> *This is a simple software engineering verified fact*
>>>>
>>>
>>> Note that olcott defines 'verified fact' as 'proven fact', but he is 
>>> unable to show the proof. So, it must be read as 'my belief'.
>>
>> It is self-evidently true to anyone having sufficient knowledge
>> of the semantics of the C programming language.
> 
> No, it isn't, because the C code of H is not shown. 

*I DON'T KNOW WHY I MUST REPEAT THIS HUNDREDS OF TIMES*
The C code that <is> shown provides the template for the
infinite set of every D correctly simulated by H.

> The actual
> implementation of H as decribed in some earlier messages is
> not fully encoded in standard C, so in order to understand the
> behaviour of D one needs to know and understand something that
> is not given as a C code and therefore not understandable from
> mere knowing the C language definition.
> 

*SUFFICIENTLY KNOWING THE SEMANTICS OF C*
*SUFFICIENTLY KNOWING THE SEMANTICS OF C*
*SUFFICIENTLY KNOWING THE SEMANTICS OF C*

I could cast uint32_t to and from the various function pointer
types yet this is more difficult for people to understand.
I got complaints about this.
It is simpler and easier to do this: typedef int (*ptr)();


-- 
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer