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

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

On 2024-05-13 14:43:09 +0000, olcott said:
 

On 5/13/2024 4:14 AM, Mikko wrote:

On 2024-05-13 04:54:30 +0000, immibis said:
 

On 10/05/24 19:55, Alan Mackenzie wrote:

[ Followup-To: set ]
 In comp.theory olcott <polcott333@gmail.com> wrote:
 [ .... ]
 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:

 

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

 

*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*

 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 }

  .  These are the diagnostics generated by GCC:
 

And the halting problem is about Turing machines, anyway.

 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.
 

 Well put. All computable functions even if written in C.

 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.