Re: On recursion and infinite recursion (reprise #3)

From	Mr Flibble <flibble@reddwarf.jmc>
Newsgroups	comp.theory
Subject	Re: On recursion and infinite recursion (reprise #3)
Message-ID	<20220508094913.00002e7c@reddwarf.jmc> (permalink)
References	(7 earlier) <t55uvv$fpf$1@dont-email.me> <20220507152017.00000990@reddwarf.jmc> <t562a4$9ao$1@dont-email.me> <20220507161901.00002e54@reddwarf.jmc> <t57v4c$7do$1@dont-email.me>
Organization	Jupiter Mining Corp
Date	2022-05-08 09:49 +0100

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On Sun, 8 May 2022 11:31:08 +0300
Mikko <mikko.levanto@iki.fi> wrote:

> On 2022-05-07 15:19:01 +0000, Mr Flibble said:
> 
> > On Sat, 7 May 2022 18:13:08 +0300
> > Mikko <mikko.levanto@iki.fi> wrote:
> >   
> >> On 2022-05-07 14:20:17 +0000, Mr Flibble said:
> >>   
> >>> On Sat, 7 May 2022 17:16:31 +0300
> >>> Mikko <mikko.levanto@iki.fi> wrote:
> >>>   
> >>>> On 2022-05-07 14:06:12 +0000, Mr Flibble said:
> >>>>   
> >>>>> On Sat, 7 May 2022 16:59:55 +0300
> >>>>> Mikko <mikko.levanto@iki.fi> wrote:
> >>>>>   
> >>>>>> On 2022-05-07 12:42:50 +0000, Mr Flibble said:
> >>>>>>   
> >>>>>>> On Sat, 7 May 2022 12:52:58 +0300
> >>>>>>> Mikko <mikko.levanto@iki.fi> wrote:
> >>>>>>>   
> >>>>>>>> On 2022-05-06 14:02:53 +0000, Mr Flibble said:
> >>>>>>>>   
> >>>>>>>>> The decider could never be compiled and run in the first
> >>>>>>>>> place due to the category error in the definition of the
> >>>>>>>>> proof.  
> >>>>>>>> 
> >>>>>>>> An error in the definition of the proof does not prevent
> >>>>>>>> compilation and execution of the program.  
> >>>>>>> 
> >>>>>>> In this case the error in the definition of the proof  
> >>>>>> 
> >>>>>> No part of the proof is identified as errorneous, so the rest
> >>>>>> is irrelevant. Anyway,
> >>>>>>   
> >>>>>>> does prevent compilation unless  
> >>>>>> 
> >>>>>> There is no option here, so the "unless" is void.
> >>>>>>   
> >>>>>>> the decider is made part of the program that is being decided
> >>>>>>>  
> >>>>>> 
> >>>>>> The decider is made a part of the program discussed in the
> >>>>>> proof. 
> >>>>>>> in which case we get a function call-like infinite recursion
> >>>>>>> instead  
> >>>>>> 
> >>>>>> We get or we don't get, depending on how the halt decider
> >>>>>> candidate attempts to decide.
> >>>>>>   
> >>>>>>> (as described by Pete Olcott) and we are attempting (and
> >>>>>>> failing) to decide if a procedure halts rather than if a
> >>>>>>> program halts.  
> >>>>>> 
> >>>>>> In any case, the decider candidate fails to give the correct
> >>>>>> answer, and therefore is not a halt decider. Note that this is
> >>>>>> correctly inferred in the proof. Therefore either the
> >>>>>> conclusion of the proof is correct or you are wrong.  
> >>>>> 
> >>>>> No answer is ever given due to the infinite recursion.  
> >>>> 
> >>>> True about some candidates, false about others. For example, a
> >>>> candidate that always says "no" is not infinitely recursive but
> >>>> is wrong in the particular case discussed in the proof. But
> >>>> anyway, you have confirmed the conclusion of the proof.  
> >>> 
> >>> False. The proof is not cognisant of the presence of the infinite
> >>> recursion.  The decider can never return an answer of
> >>> halts/doesn't halt due to the infinite recursion.  
> >> 
> >> The correct term is decider candidate. It is not a decider because
> >> the infinite recursion prevents it from halting in finite time.
> >> 
> >> You cannot call the proof incorrect merely because it agrees with
> >> you.  
> > 
> > Try actually reading what Strachey wrote: a contradiction arises
> > based on the result of evaluating T[P] however T[P] is never
> > evaluated due to the infinite recursion: a fact ignored by the
> > proof.  
> 
> If you can prove that the program does give the correct result in that
> case you have proven Strachey wrong. Otherwise you haven't.

Strachey is wrong because he neglected to account for the infinite
recursion; this should be obvious to anyone who has actually read and
understood what Strachey wrote: it seems that you haven't.

/Flibble

Thread

On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-05 17:50 +0100
  Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-05 13:58 -0500
    Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-05 20:56 +0100
      Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-05 17:15 -0500
        Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-06 02:43 +0100
          Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-05 20:59 -0500
            Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-06 04:08 +0100
  Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-05 20:51 +0100
    Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-05 20:52 +0100
      Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-05 21:15 +0100
        Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-05 21:16 +0100
      Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-05 16:35 -0500
    Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-05 16:37 -0500
      Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-06 02:38 +0100
        Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-05 20:42 -0500
          Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-06 03:59 +0100
  Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-05 22:33 -0400
    Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-06 15:02 +0100
      Re: On recursion and infinite recursion (reprise #3) Python <python@example.invalid> - 2022-05-06 16:18 +0200
        Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-06 11:55 -0500
      Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-07 12:52 +0300
        Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-07 13:42 +0100
          Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-07 16:59 +0300
            Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-07 15:06 +0100
              Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-07 17:16 +0300
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-07 15:20 +0100
                Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-07 18:13 +0300
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-07 16:19 +0100
                Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-07 11:03 -0500
                Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-07 23:41 +0100
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-07 23:43 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-07 19:59 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 01:01 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-07 20:18 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 01:55 +0100
                Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-08 11:31 +0300
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 09:49 +0100
                Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-08 13:00 +0300
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 12:57 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-08 07:45 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 13:02 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-08 08:31 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 13:39 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-08 14:10 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 20:06 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-08 15:39 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 21:14 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-08 17:40 -0400
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-08 23:04 +0100
                Re: On recursion and infinite recursion (reprise #3) Ben <ben.usenet@bsb.me.uk> - 2022-05-09 00:26 +0100
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-08 19:40 -0400
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 10:55 -0500
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-09 20:13 -0400
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 10:51 -0500
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-09 18:31 +0100
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 12:36 -0500
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-09 20:15 -0400
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-09 20:14 -0400
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 10:49 -0500
                Re: On recursion and infinite recursion (reprise #3) Mr Flibble <flibble@reddwarf.jmc> - 2022-05-09 18:31 +0100
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 12:37 -0500
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 10:47 -0500
                Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-09 19:33 +0300
                Re: On recursion and infinite recursion (reprise #3) olcott <NoOne@NoWhere.com> - 2022-05-09 11:36 -0500
                Re: On recursion and infinite recursion (reprise #3) Richard Damon <Richard@Damon-Family.org> - 2022-05-09 20:17 -0400
                Re: On recursion and infinite recursion (reprise #3) olcott <polcott2@gmail.com> - 2022-05-07 11:06 -0500
  Re: On recursion and infinite recursion (reprise #3) Mikko <mikko.levanto@iki.fi> - 2022-05-06 16:39 +0300

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