Re: D correctly simulated by H cannot possibly reach its own line 06 and halt

Op 31.mei.2024 om 16:25 schreef olcott:

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*
 

You can assume a unicorn, but that does not make it existent. You can assume a simulating H that is a pure function and halts, but that does not make them existent. The set of such H is empty.
I stop at your first big mistake so that we can resolve this key
mistake before moving on.
D calls H and if it would be true that H halts, then D would continue with line 04. Any competent C programmer will confirm that.
Your claim is that the simulation of D does not reach line 04. That means that the simulation of H did not reach its final state. If H halts a correct simulation of H halts, too. However, the simulated H does not reach its final state, which proves that H has non-halting behaviour.
If not true, show how H halts, i.e. returns from the call from D, but D does not continue to line 04.