Re: Every D(D) simulated by H presents non-halting behavior to H ###

On 5/15/2024 3:18 AM, Mikko wrote:

On 2024-05-14 14:35:42 +0000, olcott said:
 

On 5/14/2024 4:52 AM, Mikko wrote:

On 2024-05-13 14:43:09 +0000, olcott said:
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On 5/13/2024 4:14 AM, Mikko wrote:

On 2024-05-13 04:54:30 +0000, immibis said:
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On 10/05/24 19:55, Alan Mackenzie wrote:

[ Followup-To: set ]
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In comp.theory olcott <polcott333@gmail.com> wrote:
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[ .... ]
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I've tried out your much spammed code on GCC (see below).  It is clear
you have never built or run this code, which ironically can't reach Line
06.  It can't even reach line 00.
>

Richard tried to get away with D never simulated by H as an example
of D simulated by H:

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Message-ID: <v0ummt$2qov3$2@i2pn2.org>
On 5/1/2024 7:28 PM, Richard Damon wrote:

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*That people say they know I am wrong yet will not show the detailed*
*steps of how I am wrong indicates that they are probably liars*

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You have said, or at least implied that your code fragment is runnable.
I think you are the liar, here.
>

00 int H(ptr x, ptr x)  // ptr is pointer to int function
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 }

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>
.  These are the diagnostics generated by GCC:
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And the halting problem is about Turing machines, anyway.

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Not necessarily. The same question can be asked about different machines.
The restriction to Turing machines is just one way to ensure that the
problem is well defined.
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Well put. All computable functions even if written in C.

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You still must ensure that the problem is well defined. With C there is
the problem that conforming C programs often fail to be strictly conforming.
If a program is not strictly conforming it may be interpreted as halting
by some implementation and non-halting or incorrect by another.
>

>
00 int H(ptr x, ptr x)  // ptr is pointer to int function
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 }
>
One can correctly determine that every D simulated by H
never reaches past its own line 03.

 That is not strictly conforming and hardly conforming at all.
 

What trivial syntactic error that has no effect
what-so-ever on the semantics do you believe remains?
A missing semi-colon?
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 }
The example must be simple enough so that people unfamiliar
with C will not be overwhelmed by things such as: typedef int (*ptr)();
a return value of 0 from main() also might be a little confusing.
I am trying to fit the essence of my proof on a single page.
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 past its own line 03.
This is a simple software engineering verified fact.
--
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer