Re: Why does Olcott care about simulation, anyway?

On 6/3/2024 1:56 PM, Mike Terry wrote:

On 03/06/2024 19:03, olcott wrote:

On 6/3/2024 12:36 PM, Mike Terry wrote:

On 03/06/2024 08:58, Fred. Zwarts wrote:

Op 03.jun.2024 om 02:16 schreef immibis:

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.

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Maybe because by using simulation he can shift the attention from the pathological part of the Linz proof, to another halting problem, namely that a simulating decider does not halt because it causes infinite recursion.

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PO's simulating decider does not cause infinite recursion.  That only occurs in the case where the decider performs a FULL simulation of its input, whereas typically for PO his H/HH/... perform PARTIAL simulations, where the decider monitors what is being simulated and breaks off the simulation when a particular condition is observed.
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Thanks for affirming that. You are my most technically
competent and honest reviewer.
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So yes, there is recursive simulation, but not /infinite/ recursion since at each level of simulation the simulator is free to just stop simulating at any time.  In practice this means that the outer simulator H will be the one to break out, since it will always be ahead of all the inner simulations of H in how far it has progressed.  This situation is in contrast with direct call recursion, where the outer caller has no control to break the recursion - it only regains control once the inner calls have all returned.
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PO does not properly understand this distinction.
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*You can keep ignoring this that does not make it go away*
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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)
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<Professor Sipser agreed>
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
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H can abort its simulation of D and correctly report that D specifies a
non-halting sequence of configurations.
</Professor Sipser agreed>
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*You can ignore the above forever, that does not make it away*

 I do not ignore the above.  I recently posted an example of it: a simulating HD correctly reporting non-halting after detecting a tight loop in the computation represented by its input.
 The problem with the above is with YOU.  (You misinterpret/misapply what Sipser says.)
 And of course your entire purpose behind quoting the above is just an appeal to authority.  You know that's a fallacy, because from time to time you accuse others of doing it.
 

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His own claim that D does not reach the pathological part (after line 03), displays already that the simulation is unable to process the pathological part. But the simulation introduces a new halting problem (recursive simulation), which he thinks is an answer for the original halting problem.

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You're using PO's phrase "pathological" but that is a bad (misleading) term because it suggests there is something WRONG/BAD (aka sick?) in the situation.  E.g. H processing input which is a description of its own source code.  There is nothing whatsoever wrong with that - it's just that PO gets confused by it and so argues to ban it.  Perhaps there  is an alternative term that doesn't have the deliberate connotation of "sickness".
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Mike.
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*Two PhD computer science professors disagree*
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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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E C R Hehner. *Objective and Subjective Specifications*
WST Workshop on Termination, Oxford.  2018 July 18.
See https://www.cs.toronto.edu/~hehner/OSS.pdf
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Bill Stoddart. *The Halting Paradox*
20 December 2017
https://arxiv.org/abs/1906.05340
arXiv:1906.05340 [cs.LO]
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*You can ignore the above forever, that does not make it away*
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 Well, it kinda DOES.  This is just a blatant appeal to authority on your part, so it can rightly be ignored.  I'll say again - if you have some argument to make, argue it yourself in your own words rather than attempting to shut down discussion through appeal to authority.
 

*Those were my verbatim words that professor Sipser agreed to*
All the people that tried to show how I misinterpreted my own words
utterly failed.
Those that claimed Professor Sipser understood my words differently than
I did had only one basis that I remember being presented that is easily
proven false. *They tried to get away with contradicting this*
DD correctly emulated by any HH that can possibly exist DOES NOT HALT
DD correctly emulated by any HH that can possibly exist DOES NOT HALT
DD correctly emulated by any HH that can possibly exist DOES NOT HALT
typedef int (*ptr)();  // ptr is pointer to int function in C
00       int HH(ptr p, ptr i);
01       int DD(ptr p)
02       {
03         int Halt_Status = HH(p, p);
04         if (Halt_Status)
05           HERE: goto HERE;
06         return Halt_Status;
07       }
_DD()
[00001c22] 55         push ebp
[00001c23] 8bec       mov ebp,esp
[00001c25] 51         push ecx
[00001c26] 8b4508     mov eax,[ebp+08]
[00001c29] 50         push eax        ; push DD 1c22
[00001c2a] 8b4d08     mov ecx,[ebp+08]
[00001c2d] 51         push ecx        ; push DD 1c22
[00001c2e] e80ff7ffff call 00001342   ; call HH
[00001c33] 83c408     add esp,+08
[00001c36] 8945fc     mov [ebp-04],eax
[00001c39] 837dfc00   cmp dword [ebp-04],+00
[00001c3d] 7402       jz 00001c41
[00001c3f] ebfe       jmp 00001c3f
[00001c41] 8b45fc     mov eax,[ebp-04]
[00001c44] 8be5       mov esp,ebp
[00001c46] 5d         pop ebp
[00001c47] c3         ret
Size in bytes:(0038) [00001c47]

[Perhaps Hehner/Stoddart are just idiots who got things wrong, or much more likely you've completely misinterpreted what they're saying, or you've misunderstood the context or whatever and you are the idiot.  The bottom line is THEY ARE NOT HERE ARGUING ANY CASE SO WHAT YOU SAY THEY BELIEVE IS TOTALLY IRRELEVANT.  And there's no need for anyone to get into discussions over whether it is Hehner/Stoddart or yourself who is confused...]
  Mike.
 

After many extensive conversations with professor Hehner:
   His most relevant belief is that the halting problem cannot
   be solved because there is something wrong with it.
Professor Hehner: Yes, I would sign that statement.
*My concise summation of the error*
The way that the halting problem is conventionally understood is that H
must correctly answer yes or no to an input that contradicts both
answers, thus H is being asked a question isomorphic to the Liar
Paradox: Is this sentence true or false: "This sentence is not true." ?
Professor Hehner got to something very much like that in his 2018 paper
with his Carol's question.  https://www.cs.toronto.edu/~hehner/OSS.pdf
--
Copyright 2024 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer