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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: Every D correctly simulated by H never reaches its final state and halts
Date: Tue, 21 May 2024 12:39:51 +0300
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On 2024-05-20 17:53:59 +0000, olcott said:

> On 5/20/2024 3:08 AM, Mikko wrote:
>> On 2024-05-19 13:59:09 +0000, olcott said:
>> 
>>> On 5/19/2024 8:43 AM, Mikko wrote:
>>>> On 2024-05-19 12:36:08 +0000, olcott said:
>>>> 
>>>>> On 5/19/2024 5:37 AM, Mikko wrote:
>>>>>> On 2024-05-18 14:38:53 +0000, olcott said:
>>>>>> 
>>>>>>> On 5/18/2024 4:45 AM, Mikko wrote:
>>>>>>>> On 2024-05-17 15:55:03 +0000, olcott said:
>>>>>>>> 
>>>>>>>>> On 5/17/2024 4:08 AM, Mikko wrote:
>>>>>>>>>> On 2024-05-17 07:25:52 +0000, Fred. Zwarts said:
>>>>>>>>>> 
>>>>>>>>>>> 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'.
>>>>>>>>>> 
>>>>>>>>>> A "proven fact" without a proof is not worse than a "verified fact"
>>>>>>>>>> without a verification.
>>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> *I updated my wording*
>>>>>>>>> It is self-evidently true to anyone having sufficient knowledge
>>>>>>>>> of the semantics of the C programming language.
>>>>>>>> 
>>>>>>>> No, it is not. I would know if it were.
>>>>>>>> 
>>>>>>> 
>>>>>>> If you do not understand that a single valid counter-example
>>>>>>> would refute my claim then you don't know enough about proofs.
>>>>>> 
>>>>>> Your claim
>>>>>> 
>>>>> 
>>>>> Most people to not know the difference between deductive proof
>>>>> ]and inductive evidence.
>>>> 
>>>> Most people don't read comp.theory so here we needn't care.
>>>> 
>>> 
>>> If anyone is trying to prove me wrong they
>>> must first understand what an actual proof is.
>>> 
>>> Several people here seem to think that ad hominem personal
>>> attacks and insults are the basis for a valid rebuttal.
>>> 
>>> Richard has stated that he thinks that an example of
>>> {D never simulated by H} ∈ {every D simulated by H}
>> 
>> More generally, everybody who knows what ∈ usually means,
>> thinks that {} ∈ X is true unless it is a syntax error.
>> 
> 
> According to that reasoning everyone
> thinks that {cats} ∈ {dogs} is true.

Apparently your interpretation of either "that reasoning" or
"everyone" is different from mine.

-- 
Mikko