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From: olcott <polcott333@gmail.com>
Newsgroups: comp.theory
Subject: Re: Deciders are ONLY accountable for their actual inputs ---
Date: Mon, 3 Jun 2024 07:52:22 -0500
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On 6/3/2024 3:35 AM, Mikko wrote:
> On 2024-06-02 13:46:30 +0000, olcott said:
> 
>> On 6/2/2024 2:56 AM, Mikko wrote:
>>> On 2024-06-01 14:44:50 +0000, olcott said:
>>>
>>>> On 6/1/2024 2:56 AM, Mikko wrote:
>>>>> On 2024-05-31 14:25:40 +0000, olcott said:
>>>>>
>>>>>> On 5/31/2024 2:50 AM, Fred. Zwarts wrote:
>>>>>>> Op 31.mei.2024 om 00:01 schreef olcott:
>>>>>>>> On 5/30/2024 4:54 PM, joes wrote:
>>>>>>>>> Am Thu, 30 May 2024 09:55:24 -0500 schrieb olcott:
>>>>>>>>>
>>>>>>>>>> typedef int (*ptr)();  // ptr is pointer to int function in C
>>>>>>>>>> 00       int H(ptr p, ptr i);
>>>>>>>>>> 01       int D(ptr p)
>>>>>>>>>> 02       {
>>>>>>>>>> 03         int Halt_Status = H(p, p);
>>>>>>>>>> 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       }
>>>>>>>>>>
>>>>>>>>>> The left hand-side are line numbers of correct C code.
>>>>>>>>>> This code does compile and does conform to c17.
>>>>>>>>>>
>>>>>>>>>> Everyone with sufficient knowledge of C can easily determine 
>>>>>>>>>> that D
>>>>>>>>>> correctly emulated by any *pure function* H (using an x86 
>>>>>>>>>> emulator)
>>>>>>>>>> cannot possibly reach its own simulated final state at line 06 
>>>>>>>>>> and halt.
>>>>>>>>> Yeah, of course not, if H doesn’t halt.
>>>>>>>>>
>>>>>>>>
>>>>>>>> To actually understand my words (as in an actual honest dialogue)
>>>>>>>> you must pay careful attention to every single word. Maybe you
>>>>>>>> had no idea that *pure functions* must always halt.
>>>>>>>>
>>>>>>>> Or maybe you did not know that every computation that never reaches
>>>>>>>> its own final state *DOES NOT HALT* even if it stops running 
>>>>>>>> because
>>>>>>>> it is no longer simulated.
>>>>>>>
>>>>>>> Since the claim is that H is also a computation, it holds for H, 
>>>>>>> as well. That means that H *DOES NOT HALT* even if it stops 
>>>>>>> running because it is no longer simulated.
>>>>>>>
>>>>>>
>>>>>> *pure function H definitely halts you are confused*
>>>>>
>>>>> A pure function does not halt (in C that means that a pure function
>>>>> does not call exit). A pure function returns.
>>>>>
>>>>
>>>> When a pure function returns this is the equivalent of the theory
>>>> of computation halting.
>>>
>>> In ceratin sense, yes. But the term "pure function" is mainly used
>>> in a different context where the word "halting" has a more specific
>>> meaning.
>>>
>>
>> I need to maintain a constant mapping between theory of computation
>> terminology and software engineering terminology.
> 
> You need to keep your own terminology consistent and well defined.
> If possible try to avoid terms that have different meanings in
> the two areas.
> 
>> Computable Function(comp sci) <is equivalent to> Pure function(SE)
>> I want it to be easy for software engineers to understand my proof.
> 
> If you want to write to software engineers you need to define all
> terms that are not software engneers terms or do not mean what
> they mean in oftware engineering or do not have the same meaning
> to all software engineers. Software engineers borrow terms from
> their application areas and tool providers which result term
> conflicts as application areas and tool providers are not the same
> for all software engineers.
> 
>> Only software engineers will understand that DD correctly simulated
>> by HH had different behavior than DD(DD). Comp Sci people allow Comp Sci
>> dogma to overrule verified facts.
> 
> A relevant dogma always overrides an irrelevant fact.
> 

Nothing can override any fact without lying.

>> When I pinned Richard down on this he simply said that he does not 
>> care that DD correctly simulated by HH has different behavior than 
>> DD(DD).
> 
> Those behaviour are obiously different as only the latter has
> a specified input. But why would anybody care?
> 

The input to HH(DD,DD) specifies non-halting behavior.
You can lie about it what you can't do is show that it is not true.

>> It turns out that DD correctly simulated by HH <is> the behavior that
>> the input to HH(DD,DD) specifies. Deciders are ONLY accountable for
>> their actual inputs. Deciders compute the mapping FROM THEIR INPUTS...
> 
> It does not turn out. Input does not specify. Problem statements specify.
> Specifications and contracts specify or at least try to specify. Inputs
> are something that can mentioned and considered in specifications.
> 

DD correctly emulated by any HH that can possibly exist DOES NOT HALT
DD correctly emulated by any HH that can possibly exist DOES NOT HALT
DD correctly emulated by any HH that can possibly exist DOES NOT HALT

typedef int (*ptr)();  // ptr is pointer to int function in C
00       int HH(ptr p, ptr i);
01       int DD(ptr p)
02       {
03         int Halt_Status = HH(p, p);
04         if (Halt_Status)
05           HERE: goto HERE;
06         return Halt_Status;
07       }

_DD()
[00001c22] 55         push ebp
[00001c23] 8bec       mov ebp,esp
[00001c25] 51         push ecx
[00001c26] 8b4508     mov eax,[ebp+08]
[00001c29] 50         push eax        ; push DD 1c22
[00001c2a] 8b4d08     mov ecx,[ebp+08]
[00001c2d] 51         push ecx        ; push DD 1c22
[00001c2e] e80ff7ffff call 00001342   ; call HH
[00001c33] 83c408     add esp,+08
[00001c36] 8945fc     mov [ebp-04],eax
[00001c39] 837dfc00   cmp dword [ebp-04],+00
[00001c3d] 7402       jz 00001c41
[00001c3f] ebfe       jmp 00001c3f
[00001c41] 8b45fc     mov eax,[ebp-04]
[00001c44] 8be5       mov esp,ebp
[00001c46] 5d         pop ebp
[00001c47] c3         ret
Size in bytes:(0038) [00001c47]

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