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On 6/3/24 10:18 PM, olcott wrote:
> On 6/3/2024 8:59 PM, Richard Damon wrote:
>> On 6/3/24 9:46 PM, olcott wrote:
>>> On 6/3/2024 8:38 PM, Mike Terry wrote:
>>>> On 03/06/2024 18:54, olcott wrote:
>>>>> On 6/3/2024 11:25 AM, Mike Terry wrote:
>>>>>> On 03/06/2024 04:50, olcott wrote:
>>>>>>> On 6/2/2024 10:28 PM, Mike Terry wrote:
>>>>>>>> On 03/06/2024 01:16, immibis wrote:
>>>>>>>>> The halting problem says you can't find a Turing machine that
>>>>>>>>> tells whether executing each other Turing machine will halt.
>>>>>>>>> Simulation has nothing to do with the question.
>>>>>>>>
>>>>>>>> Background:
>>>>>>>>
>>>>>>>> PO claims to have refuted the common HP proof, e.g. as covered
>>>>>>>> in the Linz book "An Introduction to Formal Languages and
>>>>>>>> Automata". PO occasionally posts a link to a PDF containing an
>>>>>>>> extract of the 5 or so pages of the book containing the proof,
>>>>>>>> but I expect you have access to this or equivalent.
>>>>>>>>
>>>>>>>> In a nutshell, the proof goes:
>>>>>>>> - Suppose H is a TM Halt decider that decides for any input
>>>>>>>> whether
>>>>>>>> TM P run with input I on its input tape halts.
>>>>>>>> [
is the string representation of the actual TM P, and
>>>>>>>> is the string representation of input tape I]
>>>>>>>> - Construct from H a new TM H^ using the mechanical process
>>>>>>>> described in the proof.
>>>>>>>> If H exists, then its corresponding H^ also exists.
>>>>>>>> - Show that the construction of H^ ensures that:
>>>>>>>> - if H decides input (representing H^ running with
>>>>>>>> input ) halts,
>>>>>>>> then that implies that H^ running with input never
>>>>>>>> halts
>>>>>>>> - if H decides input never halts,
>>>>>>>> then that implies H^ running with input halts
>>>>>>>> I.e. either way, H decides the specific input
>>>>>>>> incorrectly, contradicting
>>>>>>>> the initial assumption that H is a halt decider.
>>>>>>>> - So no halt decider exists. (Every proposed halt decider
>>>>>>>> decides at least one input case
>>>>>>>> incorrectly, viz input .)
>>>>>>>>
>>>>>>>> PO basically claimed he had a fully coded TM H, which CORRECTLY
>>>>>>>> decides its "nemesis" input , contradicting the logic of
>>>>>>>> the Linz proof [without pointing out any actual mistake in the
>>>>>>>> Linz proof]. Given most people here understand the Linz proof
>>>>>>>> well enough to see it is basically sound, people were sceptical!
>>>>>>>>
>>>>>>>> It turned out PO was lying about the fully coded TM, and in fact
>>>>>>>> what he actually had was the idea behind a C program which would
>>>>>>>> "prove" his idea. A couple of years(?) later he actually
>>>>>>>> completed his C program and his x86utm.exe which would simulate
>>>>>>>> the x86 code of his H and H^ to "prove" his claim. His
>>>>>>>> equivalent of Linz H is his C function H or HH, and his
>>>>>>>> equivalent of Linz H^ is his D or DD respectively. (They run
>>>>>>>> under x86utm.exe and are not Windows/Unix executables.)
>>>>>>>>
>>>>>>>> H/HH use PARTIAL simulation of their input to decide
>>>>>>>> halting/non-halting, returning
>>>>>>>> 0 or 1 to communicate their decision. As you correctly point
>>>>>>>> out, to the HP proof simulation is quite irrelevant, being just
>>>>>>>> one kind of data manipulation that H may perform on its input
>>>>>>>> string before it decides the halting status. So the Linz
>>>>>>>> HP proof covers such H, no problem.
>>>>>>>> [I put PARTIAL in caps, just because there seems to be some
>>>>>>>> confusion in recent threads as to what PO means by "simulation".
>>>>>>>> He doesn't say it explicitly, despite suggestions to this
>>>>>>>> effect, but he always means what might be called /partial/
>>>>>>>> simulation.]
>>>>>>>>
>>>>>>>> PO believes that by (partially) simulating the computation
>>>>>>>> corresponding to the input
[i.e. calculating the
>>>>>>>> successive x86 instruction steps of the computation P(I)] and
>>>>>>>> monitoring the progress of virtual x86 state changes (like
>>>>>>>> instruction address and op-code and so on) H could spot some
>>>>>>>> pattern that reveals whether computation P(I) halts or not. At
>>>>>>>> this point in the partial simulation, his H would stop
>>>>>>>> simulating (aka "abort" the simulation) and return the
>>>>>>>> appropriate halt status for input
.
>>>>>>>>
>>>>>>>> Nothing remarkable so far! Clearly a tight-loop in P /can/ be
>>>>>>>> detected in this fashion, so /some/
inputs /can/ be
>>>>>>>> correctly determined like this. The PO claim however is that
>>>>>>>> the specific input is correctly decided by his H. In C
>>>>>>>> terms those correspond to H(D,D) correctly returning the halt
>>>>>>>> status of computation D(D). [PO would probably dispute this,
>>>>>>>> because he doesn't properly understand halting or the HP
>>>>>>>> generally, or in fact pretty much /any abstract concept/ ]
>>>>>>>>
>>>>>>>
>>>>>>> Introduction to the Theory of Computation, by Michael Sipser
>>>>>>> https://www.amazon.com/Introduction-Theory-Computation-Michael-Sipser/dp/113318779X/
>>>>>>>
>>>>>>> On 10/13/2022 11:29:23 AM
>>>>>>> MIT Professor Michael Sipser agreed this verbatim paragraph is
>>>>>>> correct
>>>>>>> (He has neither reviewed nor agreed to anything else in this paper)
>>>>>>>
>>>>>>>
>>>>>>> If simulating halt decider H correctly simulates its input D until H
>>>>>>> correctly determines that its simulated D would never stop running
>>>>>>> unless aborted then
>>>>>>>
>>>>>>> H can abort its simulation of D and correctly report that D
>>>>>>> specifies a
>>>>>>> non-halting sequence of configurations.
>>>>>>>
>>>>>>>
>>>>>>> I have started working on what seem to be some computability issues
>>>>>>> that you pointed out with my HH. I found that they are isolated to
>>>>>>> one single element of HH. Essentially the details of how the master
>>>>>>> UTM directly executed HH passes a portion of its tape to its slaves.
>>>>>>>
>>>>>>> Nothing else seems to have any computability issues by the measure
>>>>>>> that I am using.
>>>>>>>
>>>>>>> Message-ID:
>>>>>>> On 3/1/2024 12:41 PM, Mike Terry wrote:
>>>>>>> >
>>>>>>> > Obviously a simulator has access to the internal state
>>>>>>> > (tape contents etc.) of the simulated machine. No problem there.
>>>>>>>
>>>>>>> Because of your above comment it seems that correcting this
>>>>>>> tiny computability issue with HH is my best path forward.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> You have given the following a blatantly false review when I
>>>>>>> said the same thing another way:
>>>>>>
>>>>>> I have no idea what you're talking about. I did not write any of
>>>>>> what follows below.
>>>>>>
>>>>>> Also I don't believe I said anything "blatantly false". You're
>>>>>> incapable of judging what other people say or are thinking -
>>>>>> you're often telling people that they'er lying to you and denying
>>>>>> "previously verified facts" etc. but its all rubbish - you're in
>>>>>> no position to make such judgements.
>>>>>>
>>>>>>
>>>>>> Mike.
>>>>>>
>>>>>
>>>>> You said that the execution trace that I proved is correct is
>>>>> incorrect because you didn't like the way that HH was written.
>>>>> You said this without looking at my proof as you are doing
>>>>> here again.
>>>>
>>>> An execution trace that is produced by a program that is incorrect
>>>> /proves/ nothing whatsoever. I don't need to look at your proof, as
>>>> I was commenting on the value of your program output AS PROOF.
>>>>
>>>
>>> I provided the execution trace that HH derives
>>> *AND THE X86 SOURCE-CODE OF DD THAT PROVES THIS TRACE IS CORRECT*
>>> *AND THE X86 SOURCE-CODE OF DD THAT PROVES THIS TRACE IS CORRECT*
>>> *AND THE X86 SOURCE-CODE OF DD THAT PROVES THIS TRACE IS CORRECT*
>>
>> Then why did the trace not follow the call to H?
>>
>
> HH(DD,DD) the trace does follow the call to HH(DD,DD)
> and fully simulates itself simulating DD.
So, where are the instuctions of HH shown?
I guess you are just a LIAR.
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