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Groups > comp.theory > #36406

Re: Halting problem erroneously defined

From Alan Mackenzie <acm@muc.de>
Newsgroups comp.theory
Subject Re: Halting problem erroneously defined
Date 2021-07-16 16:39 +0000
Organization muc.de e.V.
Message-ID <scsco1$1r61$1@news.muc.de> (permalink)
References <20210715182217.00002c8c@reddwarf.jmc> <yKudnbQsIpYNGm39nZ2dnUU78R_NnZ2d@brightview.co.uk> <20210716133319.000033a8@reddwarf.jmc> <scs60c$e50$1@news.muc.de> <yaqdnTVRhofYAGz9nZ2dnUU7-fPNnZ2d@giganews.com>

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[ Offensive cross-posts removed. ]

In comp.theory olcott <NoOne@nowhere.com> wrote:
> On 7/16/2021 9:44 AM, Alan Mackenzie wrote:
>> Mr Flibble <flibble@reddwarf.jmc> wrote:
>>> On Thu, 15 Jul 2021 20:08:00 +0100
>>> Mike Terry <news.dead.person.stones@darjeeling.plus.com> wrote:

>> [ .... ]

>>>> HE'S CONFIRMING THAT THE THEOREM IS CORRECT, and has a short proof
>>>> which he then outlines!

>>> NO HE ISN'T. He is saying that T cannot exist as a decider of P ....

>> He's saying that T cannot exist as a _universal_ decider, because there
>> exists a program it cannot decide correctly.

>>> .... because P is aware of T and attempts to defeat it;

>> That's unsuitably anthropomorphic langauage.  There is no "awareness" in
>> T.

>>> this DOES NOT MEAN that a T cannot decide P where P isn't attempting
>>> to defeat T by recursively referencing it.

>> Of course not.  Such a T is called a partial halting decider.  Its
>> existence has nothing to do with the non-existence of a _universal_
>> halting decider.

>> Ditto about "attempting" and "defeat".  The plain fact is, for any T,
>> there exists a P which it incorrectly decides.

>>> This is why ....

>> "what", perhaps?

>>> .... Strachen refers to is as an "impossible program".

>> He proves there is no such T, yes.

>>> /Flibble


> Conventionally it is understood that the instance of P proves that there 
> cannot be any T that always correctly decides the halting status of 
> every input.

"Conventionally" here means by everybody but cranks.  I don't recall any
other candidate false assumption being proffered on these interminable
threads.

> // The C equivalent of [Strachey 1965] CPL
> void P(u32 x)
> {
>   if (H(x, x))
>     HERE: goto HERE;
> }

> int main()
> {
>   Output("Input_Halts = ", H((u32)P, (u32)P));
> }

> In the case of my H and P, because my H is a simulating halt decider 
> that only acts as a pure simulator until after its halt status decision 
> is made the pathological self-reference(olcott 2004) error Flibble 
> correctly objects to has no effect on either the behavior of P or the 
> halt status decision of H.

The internal mechanism of H isn't of much interest.  It doesn't matter.
As long as it purports to return the halting status of any program/input
pair, there will be such a pair it gets wrong.

> H aborts the simulation of its input before any nested H ever returns 
> any value to any P. This utterly nullifies the prior issue that seemed 
> to prove that P is an undecidable input.

I can't be bothered even to make sense of that.  Whatever, any H is not a
universal halting decider.

> When the simulation of P is aborted P stops running. This does not count 
> as a P that halts. P has had its execution suspended, not halted.

P(P) either halts or it doesn't.  H gets the wrong anwer.


> -- 
> Copyright 2021 Pete Olcott

> "Great spirits have always encountered violent opposition from mediocre 
> minds." Einstein

-- 
Alan Mackenzie (Nuremberg, Germany).

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Thread

Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-15 18:22 +0100
  Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 12:42 -0500
    Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-15 18:48 +0100
      Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-15 19:00 +0100
        Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 13:04 -0500
          Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-15 19:09 +0100
            Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 13:17 -0500
      Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 13:01 -0500
  Re: Halting problem erroneously defined Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2021-07-15 20:08 +0100
    Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 15:57 -0500
      Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-15 23:06 +0100
        Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 18:00 -0500
          Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 01:29 +0100
            Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 19:59 -0500
              Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 02:49 +0100
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-15 21:43 -0500
                Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-17 01:29 +0100
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-17 11:05 -0500
                Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-18 02:36 +0100
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-19 10:09 -0500
                Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-19 08:18 -0700
                Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 01:38 +0100
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-20 09:29 -0500
                Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-20 09:17 -0700
                Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-21 01:28 +0100
                Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-17 21:57 -0600
    Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 13:25 +0100
      Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 08:56 -0500
    Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 13:33 +0100
      Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 09:28 -0500
      Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-16 14:44 +0000
        Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 09:52 -0500
          Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-16 16:39 +0000
            Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 12:13 -0500
              Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 18:26 +0100
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 12:41 -0500
                Re: Halting problem erroneously defined Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 19:37 +0100
              Re: Halting problem erroneously defined André G. Isaak <agisaak@gm.invalid> - 2021-07-16 11:53 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 13:39 -0500
                Re: Halting problem erroneously defined André G. Isaak <agisaak@gm.invalid> - 2021-07-16 12:52 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 14:40 -0500
                Re: Halting problem erroneously defined André G. Isaak <agisaak@gm.invalid> - 2021-07-16 13:57 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 15:09 -0500
                Re: Halting problem erroneously defined André G. Isaak <agisaak@gm.invalid> - 2021-07-16 14:30 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 16:06 -0500
                Re: Halting problem erroneously defined André G. Isaak <agisaak@gm.invalid> - 2021-07-16 16:09 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 17:24 -0500
                Re: Halting problem erroneously defined André G. Isaak <agisaak@gm.invalid> - 2021-07-16 16:48 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-17 10:22 -0500
                Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-17 22:24 -0600
                Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-17 22:09 -0600
                Re: Halting problem erroneously defined Jeff Barnett <jbb@notatt.com> - 2021-07-16 13:51 -0600
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 14:57 -0500
                Re: Halting problem erroneously defined Jeff Barnett <jbb@notatt.com> - 2021-07-16 16:34 -0600
              Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-16 18:25 +0000
                Re: Halting problem erroneously defined Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 19:29 +0100
                Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-16 18:59 +0000
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 14:42 -0500
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 14:22 -0500
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 14:33 -0500
                Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-16 20:19 +0000
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 15:34 -0500
                Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-16 21:30 +0000
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 16:57 -0500
                Re: Halting problem erroneously defined Alan Mackenzie <acm@muc.de> - 2021-07-17 09:39 +0000
                Re: Halting problem erroneously defined [AM] olcott <NoOne@NoWhere.com> - 2021-07-17 10:11 -0500
                Re: Halting problem erroneously defined [AM] Alan Mackenzie <acm@muc.de> - 2021-07-17 17:41 +0000
                Re: Halting problem erroneously defined [AM] olcott <NoOne@NoWhere.com> - 2021-07-17 13:26 -0500
              Re: Halting problem erroneously defined wij <wyniijj@gmail.com> - 2021-07-16 11:45 -0700
                Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-16 14:37 -0500
                Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-17 22:28 -0600
              Re: Halting problem erroneously defined Jeff Barnett <jbb@notatt.com> - 2021-07-16 13:31 -0600
          Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-17 22:06 -0600
  Re: Halting problem erroneously defined wij <wyniijj@gmail.com> - 2021-07-17 03:01 -0700
  Re: Halting problem erroneously defined Charlie-Boo <shymathguy@gmail.com> - 2021-07-19 07:35 -0700
    Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-19 15:45 -0500
      Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-19 20:44 -0700
  Re: Halting problem erroneously defined Charlie-Boo <shymathguy@gmail.com> - 2021-07-19 07:43 -0700
    Re: Halting problem erroneously defined olcott <NoOne@NoWhere.com> - 2021-07-19 15:49 -0500
      Re: Halting problem erroneously defined Richard Damon <Richard@Damon-Family.org> - 2021-07-19 20:46 -0700

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