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From: olcott <polcott333@gmail.com>
Newsgroups: comp.theory,sci.logic
Subject: Re: D correctly simulated by pure function H cannot possibly reach
 its, own line 06 --- Dishonest?
Date: Sun, 26 May 2024 09:13:04 -0500
Organization: A noiseless patient Spider
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On 5/26/2024 6:43 AM, Richard Damon wrote:

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       }


> Because, as I have said, the answer and reasoning changes depending on 
> what you acknowledged are the implications of your stipulations. For 
> instance, if your actual understanding of being a "Pure Function" is 
> that the program is the equivalent of a Turing Machine, then we need to 
> add a strictness to the definition that isn't normally used for just 
> "Pure Functions", like accessing value of registers like the program 
> counter or stack pointer might not be allowed in some cases. (which 
> breaks you H).
> 

Since we can see (and you already agreed) that D correctly simulated
by pure simulator H remains stuck in infinite recursive simulation then
we also know that D never reaches its own line 06 and halts in less
than an infinite number of correctly simulated steps.

This is what I had in mind all along. Because I am a relatively
terrible communicator it takes me a very long time to translate
my intuitions into simple words.

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