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Groups > comp.theory > #36593

Re: Halting Problem Solved

From Andy Walker <anw@cuboid.co.uk>
Newsgroups comp.theory
Subject Re: Halting Problem Solved
Date 2021-07-18 12:13 +0100
Organization Not very much
Message-ID <sd12d2$1hj5$1@gioia.aioe.org> (permalink)
References (3 earlier) <scsnmk$25df$3@news.muc.de> <20210716205629.00006506@reddwarf.jmc> <scuq00$f3u$1@dont-email.me> <yqednYuPEb9_mm79nZ2dnUU7-N3NnZ2d@giganews.com> <sd0t3v$s8h$1@dont-email.me>

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On 18/07/2021 10:43, David Brown wrote:
["You" == PO, of course]
> It would mean you have a claim (without proof - but we are assuming you
> are correct) that you can find an algorithm H that correctly tells if a
> given computation will halt or not, but only works for some functions.
> If you call H with input (P, X) which it likes, it will correctly give
> out yes or no.  If it doesn't like (P, X) - the input is "pathological",
> then it might say "yes", it might say "no", it might say "neither", it
> might never stop with an answer.

	Well, /that/ claim is trivially true, eg if "H" replies "don't
know" to every instance presented to it.  There are also less trivial
"H"'s, eg one that emulates "P(X)", replies "yes" if the emulation halts,
"no" if it repeats exactly a previous state , and otherwise either just
keeps going or else gives up after some large number of steps.

	AFAACT, given the amount of obfuscation around it, PO's
current emulator is broadly of this type.  It has though, of course,
nothing to do with the actual Halting Problem or related proofs.

> Basically, it would be useless.

	Although the sentiment is correct, your claim isn't.  There are
/useful/ programs that correctly reply "yes", correctly reply "no", or
halt and reply "sorry, can't tell".  [Proof checkers are of this general
nature.]  Basically, the third response is not [necessarily] caused by
pathology, but could be thought of as a plea for more information.  As
a debugging aid, "H" could point out the constructions that prevent it
from reaching a definite conclusion, such as uncounted loops without
[eg] corresponding invariants proving that the loop terminates.  This
serves as a hint to the programmer that [eg] an extra check is needed.
A lot of relevant analysis is already done by aggressive optimisation,
which is a closely-related area of program analysis.

-- 
Andy Walker, Nottingham.
    Andy's music pages: www.cuboid.me.uk/andy/Music
    Composer of the day: www.cuboid.me.uk/andy/Music/Composers/Kontski

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Thread

Halting Problem Solved (Black Box Decider Theory) Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 19:00 +0100
  Re: Halting Problem Solved (Black Box Decider Theory) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 19:28 +0100
    Re: Halting Problem Solved (Black Box Decider Theory) Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 19:31 +0100
      Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 14:24 -0500
      Re: Halting Problem Solved (Black Box Decider Theory) Alan Mackenzie <acm@muc.de> - 2021-07-16 19:46 +0000
        Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 14:56 -0500
        Re: Halting Problem Solved (Black Box Decider Theory) Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 20:56 +0100
          Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 15:00 -0500
            Re: Halting Problem Solved (Black Box Decider Theory) Alan Mackenzie <acm@muc.de> - 2021-07-16 22:42 +0000
          Re: Halting Problem Solved (Black Box Decider Theory) Alan Mackenzie <acm@muc.de> - 2021-07-16 22:24 +0000
            Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 17:32 -0500
              Re: Halting Problem Solved (Black Box Decider Theory) Alan Mackenzie <acm@muc.de> - 2021-07-16 22:54 +0000
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] olcott <NoOne@NoWhere.com> - 2021-07-16 23:15 -0500
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Alan Mackenzie <acm@muc.de> - 2021-07-17 09:10 +0000
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] olcott <NoOne@NoWhere.com> - 2021-07-17 09:37 -0500
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-17 17:24 +0100
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] olcott <NoOne@NoWhere.com> - 2021-07-17 12:06 -0500
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-18 02:45 +0100
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Mr Flibble <flibble@reddwarf.jmc> - 2021-07-18 12:26 +0100
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] olcott <NoOne@NoWhere.com> - 2021-07-19 09:41 -0500
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 01:36 +0100
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Alan Mackenzie <acm@muc.de> - 2021-07-17 17:11 +0000
                Re: Halting Problem Solved (Black Box Decider Theory)[ Strachey P ] Richard Damon <Richard@Damon-Family.org> - 2021-07-17 07:40 -0600
              Re: Halting Problem Solved (Black Box Decider Theory) David Brown <david.brown@hesbynett.no> - 2021-07-17 16:47 +0200
          Re: Halting Problem Solved (Black Box Decider Theory) David Brown <david.brown@hesbynett.no> - 2021-07-17 16:37 +0200
            Re: Halting Problem Solved (Black Box Decider Theory) [ Flibble is correct ] olcott <NoOne@NoWhere.com> - 2021-07-17 11:40 -0500
              Re: Halting Problem Solved (Black Box Decider Theory) [ Flibble is correct ] David Brown <david.brown@hesbynett.no> - 2021-07-18 11:43 +0200
                Re: Halting Problem Solved Andy Walker <anw@cuboid.co.uk> - 2021-07-18 12:13 +0100
                Re: Halting Problem Solved David Brown <david.brown@hesbynett.no> - 2021-07-18 15:15 +0200
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-18 07:42 -0600
                Re: Halting Problem Solved David Brown <david.brown@hesbynett.no> - 2021-07-18 17:02 +0200
                Re: Halting Problem Solved Jeff Barnett <jbb@notatt.com> - 2021-07-18 10:12 -0600
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-18 13:22 -0500
                Re: Halting Problem Solved Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-07-18 12:30 -0700
                Re: Halting Problem Solved [ Pathological self-reference error (Olcott 2004) ] olcott <NoOne@NoWhere.com> - 2021-07-19 08:41 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-18 19:55 -0700
                Re: Halting Problem Solved David Brown <david.brown@hesbynett.no> - 2021-07-18 21:00 +0200
                Re: Halting Problem Solved Jeff Barnett <jbb@notatt.com> - 2021-07-18 14:22 -0600
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-18 20:08 -0700
                Re: Halting Problem Solved Jeff Barnett <jbb@notatt.com> - 2021-07-19 02:06 -0600
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-19 21:09 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 11:24 +0100
                Re: Halting Problem Solved Daniel Pehoushek <pehoushek1@gmail.com> - 2021-07-20 03:43 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 13:53 +0100
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 14:02 +0100
                Re: Halting Problem Solved Daniel Pehoushek <pehoushek1@gmail.com> - 2021-07-20 06:30 -0700
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-20 10:22 -0700
                Re: Halting Problem Solved David Brown <david.brown@hesbynett.no> - 2021-07-19 09:11 +0200
                Re: Halting Problem Solved "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-07-19 01:13 -0700
                Re: Halting Problem Solved "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-07-19 11:34 -0700
                Re: Halting Problem Solved Jeff Barnett <jbb@notatt.com> - 2021-07-19 02:24 -0600
                Re: Halting Problem Solved David Brown <david.brown@hesbynett.no> - 2021-07-19 13:06 +0200
                Re: Halting Problem Solved Daniel Pehoushek <pehoushek1@gmail.com> - 2021-07-19 04:52 -0700
                Re: Halting Problem Solved Daniel Pehoushek <pehoushek1@gmail.com> - 2021-07-19 08:14 -0700
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-19 08:43 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-19 21:12 -0700
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-19 09:16 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-19 21:25 -0700
                Re: Halting Problem Solved Daniel Pehoushek <pehoushek1@gmail.com> - 2021-07-20 00:38 -0700
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-19 09:43 -0500
                Re: Halting Problem Solved (Black Box Decider Theory) [ Flibble is correct ] olcott <NoOne@NoWhere.com> - 2021-07-19 09:48 -0500
        Re: Halting Problem Solved (Black Box Decider Theory) Newberry <newberryxy@gmail.com> - 2021-07-19 13:30 -0700
          Re: Halting Problem Solved (Black Box Decider Theory) "dklei...@gmail.com" <dkleinecke@gmail.com> - 2021-07-20 16:16 -0700
            Re: Halting Problem Solved (Black Box Decider Theory) André G. Isaak <agisaak@gm.invalid> - 2021-07-20 17:21 -0600
              Re: Halting Problem Solved (Black Box Decider Theory) "dklei...@gmail.com" <dkleinecke@gmail.com> - 2021-07-20 16:37 -0700
                Re: Halting Problem Solved (Black Box Decider Theory) André G. Isaak <agisaak@gm.invalid> - 2021-07-20 18:37 -0600
                Re: Halting Problem Solved (Black Box Decider Theory) Richard Damon <Richard@Damon-Family.org> - 2021-07-20 18:02 -0700
                Re: Halting Problem Solved (Black Box Decider Theory) "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-07-20 23:32 -0700
                Re: Halting Problem Solved (Black Box Decider Theory) Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2021-07-21 08:17 -0700
                Re: Halting Problem Solved (Black Box Decider Theory) André G. Isaak <agisaak@gm.invalid> - 2021-07-21 09:24 -0600
            Re: Halting Problem Solved (Black Box Decider Theory) Newberry <newberryxy@gmail.com> - 2021-07-20 23:26 -0700
      Re: Halting Problem Solved (Black Box Decider Theory) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 21:57 +0100
        Re: Halting Problem Solved (Black Box Decider Theory) Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 22:06 +0100
          Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 16:10 -0500
            Re: Halting Problem Solved (Black Box Decider Theory) Mr Flibble <flibble@reddwarf.jmc> - 2021-07-16 22:22 +0100
              Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 16:30 -0500
  Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 13:31 -0500
    Re: Halting Problem Solved (Black Box Decider Theory) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 21:46 +0100
      Re: Halting Problem Solved (Black Box Decider Theory) olcott <NoOne@NoWhere.com> - 2021-07-16 16:07 -0500
        Re: Halting Problem Solved (Black Box Decider Theory) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 23:59 +0100
          Re: Halting Problem Solved [ Ben admits that he lied ] olcott <NoOne@NoWhere.com> - 2021-07-17 10:35 -0500
            Re: Halting Problem Solved [ Ben admits that he lied ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-18 03:32 +0100
              Re: Halting Problem Solved [ Ben admits that he lied ] olcott <NoOne@NoWhere.com> - 2021-07-19 09:55 -0500
                Re: Halting Problem Solved [ Ben admits that he lied ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 01:35 +0100
                Re: Halting Problem Solved [ Ben admits that he lied ] olcott <NoOne@NoWhere.com> - 2021-07-20 09:22 -0500
                Re: Halting Problem Solved [ Ben admits that he lied ] André G. Isaak <agisaak@gm.invalid> - 2021-07-20 08:40 -0600
                Re: Halting Problem Solved [ Ben admits that he lied ] olcott <NoOne@NoWhere.com> - 2021-07-20 10:18 -0500
                Re: Halting Problem Solved [ Ben admits that he lied ] André G. Isaak <agisaak@gm.invalid> - 2021-07-20 09:29 -0600
                Re: Halting Problem Solved [ Ben admits that he lied ] Daniel Pehoushek <pehoushek1@gmail.com> - 2021-07-20 09:45 -0700
                Re: Halting Problem Solved [ Ben admits that he lied ] Richard Damon <Richard@Damon-Family.org> - 2021-07-20 10:33 -0700
                Re: Halting Problem Solved [ Ben admits that he lied ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-21 01:28 +0100
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] olcott <NoOne@NoWhere.com> - 2021-07-21 09:48 -0500
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] Richard Damon <Richard@Damon-Family.org> - 2021-07-21 09:41 -0700
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-22 01:12 +0100
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] olcott <NoOne@NoWhere.com> - 2021-07-21 20:27 -0500
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] Richard Damon <Richard@Damon-Family.org> - 2021-07-21 18:37 -0700
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] olcott <NoOne@NoWhere.com> - 2021-07-21 20:49 -0500
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] Richard Damon <Richard@Damon-Family.org> - 2021-07-21 19:01 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-22 02:49 +0100
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-21 20:57 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-21 19:19 -0700
                Re: Halting Problem Solved André G. Isaak <agisaak@gm.invalid> - 2021-07-21 20:57 -0600
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-21 22:25 -0500
                Re: Halting Problem Solved André G. Isaak <agisaak@gm.invalid> - 2021-07-21 21:50 -0600
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-21 23:40 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-21 22:26 -0700
                Re: Halting Problem Solved André G. Isaak <agisaak@gm.invalid> - 2021-07-22 00:55 -0600
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-22 08:04 -0500
                Re: Halting Problem Solved André G. Isaak <agisaak@gm.invalid> - 2021-07-22 08:23 -0600
                Re: Halting Problem Solved (title is a misnomer) olcott <NoOne@NoWhere.com> - 2021-07-22 09:52 -0500
                Re: Halting Problem Solved (title is a misnomer) Richard Damon <Richard@Damon-Family.org> - 2021-07-22 10:24 -0700
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-22 10:22 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-22 21:53 +0100
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-22 16:47 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-22 14:54 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-23 00:04 +0100
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-22 18:22 -0500
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-23 00:53 +0100
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-23 09:04 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-23 09:41 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-23 22:13 +0100
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-23 16:54 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-23 15:19 -0700
                Re: Halting Problem Solved Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-25 04:02 +0100
                Re: Halting Problem Solved André G. Isaak <agisaak@gm.invalid> - 2021-07-22 18:05 -0600
                Re: Halting Problem Solved olcott <NoOne@NoWhere.com> - 2021-07-23 08:36 -0500
                Re: Halting Problem Solved Richard Damon <Richard@Damon-Family.org> - 2021-07-23 08:51 -0700
                Re: Halting Problem Solved [ Ben admits that he lied ] [ H(P,P)==0 is correct ] "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-07-21 21:04 -0700
                Re: Halting Problem Solved [ Ben admits that he lied ] Richard Damon <Richard@Damon-Family.org> - 2021-07-19 21:17 -0700
        Re: Halting Problem Solved (Black Box Decider Theory) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-16 23:59 +0100
          Re: Halting Problem Solved (Black Box Decider Theory) [Ben is a liar ] olcott <NoOne@NoWhere.com> - 2021-07-17 10:38 -0500
            Re: Halting Problem Solved (Black Box Decider Theory) [Ben is a liar ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-18 03:12 +0100
              Re: Halting Problem Solved (Black Box Decider Theory) [Ben is a liar ] olcott <NoOne@NoWhere.com> - 2021-07-19 10:02 -0500
                Re: Halting Problem Solved (Black Box Decider Theory) [Ben is a liar ] Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-07-20 01:36 +0100
  Re: Halting Problem Solved (Black Box Decider Theory) Charlie-Boo <shymathguy@gmail.com> - 2021-07-22 08:12 -0700

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