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	<20220508133909.00007b6b@reddwarf.jmc> (permalink)
References	(11 earlier) <t57v4c$7do$1@dont-email.me> <20220508094913.00002e7c@reddwarf.jmc> <Q3OdK.15730$Bm21.3438@fx07.iad> <20220508130212.00007ab6@reddwarf.jmc> <iKOdK.8684$t72a.8070@fx10.iad>
Organization	Jupiter Mining Corp
Date	2022-05-08 13:39 +0100

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On Sun, 8 May 2022 08:31:10 -0400
Richard Damon <Richard@Damon-Family.org> wrote:

> On 5/8/22 8:02 AM, Mr Flibble wrote:
> > On Sun, 8 May 2022 07:45:52 -0400
> > Richard Damon <Richard@Damon-Family.org> wrote:
> >   
> >> On 5/8/22 4:49 AM, Mr Flibble wrote:  
> >>> 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
> >>>      
> >>
> >> No, because if T gets stuck in an infinite recursion, it is wrong,
> >> because it failed to answer in finite time.
> >>
> >> If T does answer in finite time, then there never was an infinite
> >> recursion.
> >>
> >> All you have shown is that there exists a WRONG method to build a T
> >> that gets stuck, Like a T that needs to run its input to completion
> >> to answer about it.  
> > 
> > I have shown that [Strachey, 1965] contains an infinite recursion
> > and is thus invalid.
> > 
> > /Flibble
> >   
> 
> No, you haven't. All you have shown is that one way to attempt to
> make the program that Strachev says doesn't exist, fails due to
> getting caught in infinite recursion.
> 
> That just helps confirm Strachev, not refute it.

Nope. Strachey's proof is based on a contradiction relating to
evaluating the result of T[P] however T[P] can never be evaluated if
there is an infinite recursion.

/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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