Sujet : Re: HHH(DD) does correctly reject its input as non-halting --- VERIFIED FACT
De : mikko.levanto (at) *nospam* iki.fi (Mikko)
Groupes : comp.theoryDate : 15. Jun 2025, 09:39:17
Autres entêtes
Organisation : -
Message-ID : <102m0rl$q7b3$1@dont-email.me>
References : 1 2 3 4 5
User-Agent : Unison/2.2
On 2025-06-14 13:38:48 +0000, olcott said:
On 6/14/2025 4:10 AM, Fred. Zwarts wrote:
Op 13.jun.2025 om 17:53 schreef olcott:
On 6/13/2025 5:51 AM, Mikko wrote:
On 2025-06-12 15:30:05 +0000, olcott said:
int DD()
{
int Halt_Status = HHH(DD);
if (Halt_Status)
HERE: goto HERE;
return Halt_Status;
}
It is a verified fact that DD() *is* one of the forms
of the counter-example input as such an input would
be encoded in C. Christopher Strachey wrote his in CPL.
// rec routine P
// §L :if T[P] go to L
// Return §
// https://academic.oup.com/comjnl/article/7/4/313/354243
void Strachey_P()
{
L: if (HHH(Strachey_P)) goto L;
return;
}
https://academic.oup.com/comjnl/article-abstract/7/4/313/354243? redirectedFrom=fulltext
Strachey only informally presents the idea of the proof. Formalism
and details needed in a rigorous proof is not shown.
void DDD()
{
HHH(DDD);
return;
}
_DDD()
[00002192] 55 push ebp
[00002193] 8bec mov ebp,esp
[00002195] 6892210000 push 00002192
[0000219a] e833f4ffff call 000015d2 // call HHH
[0000219f] 83c404 add esp,+04
[000021a2] 5d pop ebp
[000021a3] c3 ret
Size in bytes:(0018) [000021a3]
Exactly how would DDD correctly emulated by HHH
reach its own "ret" instruction final halt state?
Indeed, HHH fails where other world-class simulators have no problem to simulate the program specified in the input.
So you still don't understand what recursive simulation is?
What makes you think that that question is relevant here?
-- Mikko