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On 8/29/2024 3:00 AM, Mikko wrote:LIE.On 2024-08-28 11:46:58 +0000, olcott said:When a TM takes its own machine description as input
>On 8/28/2024 2:33 AM, Mikko wrote:>On 2024-08-27 13:04:26 +0000, olcott said:>
>On 8/27/2024 12:45 AM, joes wrote:>Am Mon, 26 Aug 2024 18:03:41 -0500 schrieb olcott:>On 8/26/2024 7:42 AM, Ben Bacarisse wrote:>Mike Terry <news.dead.person.stones@darjeeling.plus.com> writes:On 23/08/2024 22:07, Ben Bacarisse wrote:>>We don't really know what context Sipser was given. I got in touch>
at the time so I do know he had enough context to know that PO's
ideas were "wacky" and that had agreed to what he considered a "minor
remark". Since PO considers his words finely crafted and key to his
so-called work I think it's clear that Sipser did not take the "minor
remark" he agreed to to mean what PO takes it to mean! My own take
if that he (Sipser) read it as a general remark about how to
determine some cases, i.e. that D names an input that H can partially
simulate to determine it's halting or otherwise. We all know or
could construct some such cases.
Exactly my reading. It makes Sipser's agreement natural, because it
is both correct [with sensible interpretation of terms], and moreover
describes an obvious strategy that a partial decider might use that
can decide halting for some specific cases. No need for Sipser to be
deceptive or misleading here, when the truth suffices. (In particular
no need to employ "tricksy" vacuous truth get out clauses just to get
PO off his back as some have suggested.)
Yes, and it fits with his thinking it a "trivial remark".Is this an accurate phrasing, pete?That aside, it's such an odd way to present an argument: "I managed to
trick X into saying 'yes' to something vague". In any reasonable
collegiate exchange you'd go back and check: "So even when D is
constructed from H, H can return based on what /would/ happen if H did
not stop simulating so that H(D,D) == false is correct even though D(D)
halts?". Just imagine what Sipser would say to that!
Deciders never compute the mapping of the computation
that they themselves are contained within.
Why not? A decider always either accepts or rejects its input.
The computation that they themselves are contained within cannot
possibly be an input.
What would prevent that if the input language permits computations?
>
this is not always that same behavior as the direct
execution of the machine. It is not the same because
it is one level of indirect reference away.
*How one level of indirect reference changes the answer*But there isn't a "indirect reference" in the input, there is an actual copy.
Does this sentence:
"This sentence is not true"
have a truth value? No, it is not a truth bearer.
Does this sentence:
This sentence is not true: "This sentence is not true"
have a truth value? Yes it is true.
For example, every computation can be given to an UTM. That computationOne level of indirect reference away from the
may involve a decider X that uses the same input language. What
What prevents giving X the same input as the UTM was given?
>
computation itself can have different behavior
The direct execution of DDD() has the benefit ofWhich doesn't change the BEHAVIOR of the input, just the ability to compute that behavior.
HHH having already aborted its emulation of DDD.
DDD emulated by HHH does not have this same benefit.
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