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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: DDD correctly emulated by HHH is correctly rejected as non-halting.
Date: Sun, 14 Jul 2024 11:40:01 +0300
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On 2024-07-13 12:22:24 +0000, olcott said:

> On 7/13/2024 3:00 AM, Mikko wrote:
>> On 2024-07-12 13:20:53 +0000, olcott said:
>> 
>>> On 7/12/2024 3:03 AM, Mikko wrote:
>>>> On 2024-07-11 14:10:24 +0000, olcott said:
>>>> 
>>>>> On 7/11/2024 1:25 AM, Mikko wrote:
>>>>>> On 2024-07-10 17:53:38 +0000, olcott said:
>>>>>> 
>>>>>>> On 7/10/2024 12:45 PM, Fred. Zwarts wrote:
>>>>>>>> Op 10.jul.2024 om 17:03 schreef olcott:
>>>>>>>>> typedef void (*ptr)();
>>>>>>>>> int HHH(ptr P);
>>>>>>>>> 
>>>>>>>>> void DDD()
>>>>>>>>> {
>>>>>>>>>    HHH(DDD);
>>>>>>>>> }
>>>>>>>>> 
>>>>>>>>> int main()
>>>>>>>>> {
>>>>>>>>>    HHH(DDD);
>>>>>>>>> }
>>>>>>>> 
>>>>>>>> Unneeded complexity. It is equivalent to:
>>>>>>>> 
>>>>>>>>        int main()
>>>>>>>>        {
>>>>>>>>          return HHH(main);
>>>>>>>>        }
>>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> Every time any HHH correctly emulates DDD it calls the
>>>>>>> x86utm operating system to create a separate process
>>>>>>> context with its own memory virtual registers and stack,
>>>>>>> thus each recursively emulated DDD is a different instance.
>>>>>> 
>>>>>> However, each of those instances has the same sequence of instructions
>>>>>> that the x86 language specifies the same operational meaning.
>>>>>> 
>>>>> 
>>>>> *That is counter-factual*
>>>>> When DDD is correctly emulated by HHH according to the
>>>>> semantics of the x86 programming language HHH must abort
>>>>> its emulation of DDD or both HHH and DDD never halt.
>>>> 
>>>> There is not "must" anywhere in the semantics of the programming language.
>>>> 
>>> 
>>> The semantics of the language specifies the behavior of
>>> the machine code thus deriving the must.
>> 
>> How can one derive "must" from the semantics of the machine code?
>> 
> 
> Deciders are required to (thus must) halt.

The semantics of the x86 language does not require that, nor that any of
the programs is a decider.

-- 
Mikko