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On 7/30/2024 2:24 AM, joes wrote:then it is not a correct emuluation. PERIOD.Am Mon, 29 Jul 2024 15:32:44 -0500 schrieb olcott:On 7/29/2024 3:17 PM, joes wrote:>Am Mon, 29 Jul 2024 11:32:00 -0500 schrieb olcott:On 7/28/2024 3:40 AM, Mikko wrote:On 2024-07-27 14:21:50 +0000, olcott said:On 7/27/2024 2:46 AM, Mikko wrote:On 2024-07-26 16:28:43 +0000, olcott said:It always is except in the case where the decider is reporting on the TMHalt deciders are not allowed to report on the behavior of the actualWhat if the input is the same as the containing computation?
computation that they themselves are contained within. They are only
allowed to compute the mapping from input finite strings.
description that itself is contained within.I don't understand. "The input is not the same as the containingvoid DDD()
computation when deciding on the description of the containing
computation"?
>
{
HHH(DDD);
}
The behavior of the correct emulation of the x86 machine
language input DDD to a emulating halt decider HHH is not
the same as behavior of the direct execution of DDD when
the x86 machine language of DDD is correctly emulated
by emulating halt decider HHH that calls HHH(DDD) (itself).
When Ĥ is applied to ⟨Ĥ⟩No, you have the same error.
Ĥ.q0 ⟨Ĥ⟩ ⊢* embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qy ∞
Ĥ.q0 ⟨Ĥ⟩ ⊢* embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qn
(a) Ĥ copies its input ⟨Ĥ⟩
(b) Ĥ invokes embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩
(c) embedded_H simulates ⟨Ĥ⟩ ⟨Ĥ⟩
(d) simulated ⟨Ĥ⟩ copies its input ⟨Ĥ⟩
(e) simulated ⟨Ĥ⟩ invokes simulated embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩
(f) simulated embedded_H simulates ⟨Ĥ⟩ ⟨Ĥ⟩
(g) goto (d) with one more level of simulation
The behavior of the correct UTM simulation of the input
⟨Ĥ⟩ ⟨Ĥ⟩ to a simulating halt decider embedded_H is not the
same as behavior of the direct execution of Ĥ ⟨Ĥ⟩ when
⟨Ĥ⟩ ⟨Ĥ⟩ is correctly simulated by simulating halt decider
embedded_H. (see above)
In both cases the simulating halt decider must abort itsAs will the copy of it that it is simulating, thus it gets the wrong answer.
simulation to prevent is own infinite execution.
An executing Turing machine is not allowed to report onWhich, if it contains a copy of itself, it must report on the behavior of that copy.
its own behavior. Every decider is only allowed to report
on the behavior that its finite string input specifies.
The only case where the correct UTM simulation of an inputNope, if you try to do that, you find that your UTM isn't actually a UTM, as the DEFINITION of a UTM is that its behavior ALWAYS exactly reproduces the behavior of the machine it is simulation when that machine is directly executed.
to a simulating halt decider differs from the direct execution
of this same input is when a simulating halt decider simulates
an input that calls itself.
No one ever bothered to notice this before only because theyNo, they didn't "notice" it, because it isn't true, BY THE DEFINITIONS.
always rejected the notion of a simulating halt decider
out-of-hand without review.
Professor Hehner noticed that the conventional HP input toRight, if the "decider" tries to not be wrong, its only option is to not answer, and thus be wrong.
its decider does specify non-halting behavior:
From a programmer's point of view, if we apply an
interpreter to a program text that includes a call
to that same interpreter with that same text as
argument, then we have an infinite loop. A halting
program has some of the same character as an interpreter:
it applies to texts through abstract interpretation.
Unsurprisingly, if we apply a halting program to a program
text that includes a call to that same halting program
with that same text as argument, then we have an infinite
loop. (Hehner:2011:15)
[5] E C R Hehner. Problems with the Halting Problem,
COMPUTING2011 Symposium on 75 years of Turing Machine and
Lambda-Calculus, Karlsruhe Germany, invited, 2011 October
20-21; Advances in Computer Science and Engineering
v.10 n.1 p.31-60, 2013
https://www.cs.toronto.edu/~hehner/PHP.pdf
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