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From: Mikko <mikko.levanto@iki.fi>
Newsgroups: comp.theory
Subject: Re: Anyone with sufficient knowledge of C knows that DD specifies non-terminating behavior to HHH
Date: Sun, 23 Feb 2025 12:59:26 +0200
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On 2025-02-22 16:11:31 +0000, olcott said:

> On 2/22/2025 3:04 AM, Mikko wrote:
>> On 2025-02-21 22:35:16 +0000, olcott said:
>> 
>>> On 2/21/2025 2:18 AM, Mikko wrote:
>>>> On 2025-02-20 21:31:44 +0000, olcott said:
>>>> 
>>>>> On 2/20/2025 2:38 AM, Mikko wrote:
>>>>>> On 2025-02-20 00:31:33 +0000, olcott said:
>>>>>> 
>>>>>>> On 2/19/2025 3:01 AM, Mikko wrote:
>>>>>>>> On 2025-02-18 11:26:25 +0000, olcott said:
>>>>>>>> 
>>>>>>>>> On 2/18/2025 3:24 AM, Mikko wrote:
>>>>>>>>>> On 2025-02-17 09:05:42 +0000, Fred. Zwarts said:
>>>>>>>>>> 
>>>>>>>>>>> Op 16.feb.2025 om 23:51 schreef olcott:
>>>>>>>>>>>> On 2/16/2025 4:30 PM, joes wrote:
>>>>>>>>>>>>> Am Sun, 16 Feb 2025 15:58:14 -0600 schrieb olcott:
>>>>>>>>>>>>>> On 2/16/2025 2:02 PM, joes wrote:
>>>>>>>>>>>>>>> Am Sun, 16 Feb 2025 13:24:14 -0600 schrieb olcott:
>>>>>>>>>>>>>>>> On 2/16/2025 10:35 AM, joes wrote:
>>>>>>>>>>>>>>>>> Am Sun, 16 Feb 2025 06:51:12 -0600 schrieb olcott:
>>>>>>>>>>>>>>>>>> On 2/15/2025 2:49 AM, Mikko wrote:
>>>>>>>>>>>>>>>>>>> On 2025-02-14 12:40:04 +0000, olcott said:
>>>>>>>>>>>>>>>>>>>> On 2/14/2025 2:58 AM, Mikko wrote:
>>>>>>>>>>>>>>>>>>>>> On 2025-02-14 00:07:23 +0000, olcott said:
>>>>>>>>>>>>>>>>>>>>>> On 2/13/2025 3:20 AM, Mikko wrote:
>>>>>>>>>>>>>>>>>>>>>>> On 2025-02-13 04:21:34 +0000, olcott said:
>>>>>>>>>>>>>>>>>>>>>>>> On 2/12/2025 4:04 AM, Mikko wrote:
>>>>>>>>>>>>>>>>>>>>>>>>> On 2025-02-11 14:41:38 +0000, olcott said:
>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>>> DD  correctly simulated by HHH cannot possibly terminate normally.
>>>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>>> That claim has already shown to be false. Nothing above shows that
>>>>>>>>>>>>>>>>>>> HHH does not return 0. If it does DD also returns 0.
>>>>>>>>>>>>>>>>>> When we are referring to the above DD simulated by HHH and not
>>>>>>>>>>>>>>>>>> trying to get away with changing the subject to some other DD
>>>>>>>>>>>>>>>>>> somewhere else
>>>>>>>>>>>>>>>>> such as one that calls a non-aborting version of HHH
>>>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>>>> then anyone with sufficient knowledge of C programming knows that no
>>>>>>>>>>>>>>>>>> instance of DD shown above simulated by any corresponding instance
>>>>>>>>>>>>>>>>>> of HHH can possibly terminate normally.
>>>>>>>>>>>>>>>>> Well, then that corresponding (by what?) HHH isn’t a decider.
>>>>>>>>>>>>>>>> I am focusing on the isomorphic notion of a termination analyzer.
>>>>>>>>>>>>>>> (There are other deciders that are not termination analysers.)
>>>>>>>>>>>>>>> 
>>>>>>>>>>>>>>>> A simulating termination analyzer correctly rejects any input that
>>>>>>>>>>>>>>>> must be aborted to prevent its own non-termination.
>>>>>>>>>>>>>>> Yes, in particular itself is not such an input, because we *know* that
>>>>>>>>>>>>>>> it halts, because it is a decider. You can’t have your cake and eat it
>>>>>>>>>>>>>>> too.
>>>>>>>>>>>>>> I am not even using the confusing term "halts".
>>>>>>>>>>>>>> Instead I am using in its place "terminates normally".
>>>>>>>>>>>>>> DD correctly simulated by HHH cannot possibly terminate normally.
>>>>>>>>>>>>> What’s confusing about „halts”? I find it clearer as it does not imply
>>>>>>>>>>>>> an ambiguous „abnormal termination”. How does HHH simulate DD
>>>>>>>>>>>>> terminating abnormally, then? Why doesn’t it terminate abnormally
>>>>>>>>>>>>> itself?
>>>>>>>>>>>>> You can substitute the term: the input DD to HHH does not need to be
>>>>>>>>>>>>> aborted, because the simulated decider terminates.
>>>>>>>>>>>>> 
>>>>>>>>>>>> 
>>>>>>>>>>>> typedef void (*ptr)();
>>>>>>>>>>>> int HHH(ptr P);
>>>>>>>>>>>> 
>>>>>>>>>>>> int DD()
>>>>>>>>>>>> {
>>>>>>>>>>>>   int Halt_Status = HHH(DD);
>>>>>>>>>>>>   if (Halt_Status)
>>>>>>>>>>>>     HERE: goto HERE;
>>>>>>>>>>>>   return Halt_Status;
>>>>>>>>>>>> }
>>>>>>>>>>>> 
>>>>>>>>>>>> int main()
>>>>>>>>>>>> {
>>>>>>>>>>>>   HHH(DD);
>>>>>>>>>>>> }
>>>>>>>>>>>> 
>>>>>>>>>>>> Every simulated input that must be aborted to
>>>>>>>>>>>> prevent the non-termination of HHH is stipulated
>>>>>>>>>>>> to be correctly rejected by HHH as non-terminating.
>>>>>>>>>>>> 
>>>>>>>>>>> A very strange and invalid stipulation.
>>>>>>>>>> 
>>>>>>>>>> It merely means that the words do not have their ordinary meaning.
>>>>>> 
>>>>>> Those two comments are not discussed below.
>>>>>> 
>>>>>>>>> Unless HHH(DD) aborts its simulation of DD itself cannot possibly 
>>>>>>>>> terminate normally.
>>>>>>>> 
>>>>>>>> That cannot be determined without examination of HHH, which is not in the
>>>>>>>> scope of OP.
>>>>>>> 
>>>>>>> I have given everyone here all of the complete source
>>>>>>> code for a few years
>>>>>> 
>>>>>> True but irrelevant. OP did not specify that HHH means that particular
>>>>>> code.
>>>>>> 
>>>>> 
>>>>> Every post that I have been talking about for two or
>>>>> more years has referred to variations of that same code.
>>>> 
>>>> OP had a pointer of that code but didn's state that that code is a part
>>>> of the problem. OP did not spacify any range for variation.
>>>> 
>>> 
>>> I have only been talking about variations of the same code
>>> as HHH(DD) for two years. Do you understand that one sentence?
>> 
>> I understnd the sentence except the word "variations". What is the
>> range of "variations"?
>> 
> 
> Good you are being completely reasonable.
> There are at least two algorithms the current
> one that was also the original one is easiest to
> understand. This algorithm essentially spots the
> equivalent of infinite recursion. The code provides
> all of the details.
> 
>> Anyway OP did not specify that HHH is restricted to those "variations".
>> Another undefined word of OP is "cannot". About a person it may mean
>> that one does not do what one wants to do but a program does not want.
>> 
> 
> HHH is exactly as specified. Assuming otherwise is silly.

The words "as specified" when nothing is specified are not a good use
of the language.

-- 
Mikko