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Groups > comp.theory > #119111
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.theory |
| Subject | Re: How to write a self-referencial TM? |
| Date | 2025-05-14 14:40 -0700 |
| Organization | None to speak of |
| Message-ID | <87cycaan1t.fsf@nosuchdomain.example.com> (permalink) |
| References | (7 earlier) <1002nvo$2k04b$5@dont-email.me> <87plgb9d4i.fsf@nosuchdomain.example.com> <1002tma$2k04c$5@dont-email.me> <87ldqyapfk.fsf@nosuchdomain.example.com> <10031uo$2n1is$1@dont-email.me> |
Richard Heathfield <rjh@cpax.org.uk> writes:
[...]
> Using a highly questionable collection of approximations about the
> physical properties of 4mm mylar tape and the number of atoms in the
> universe, I calculated that by devoting /everything/ to this tape we
> could make it
>
> 5285412262156448202959830866807610993657505285
>
> lightyears long (exACtly, of course).
>
> It's still a long way off infinite, but I think it could possibly
> qualify as 'long enough'.
It's still not long enough for a TM that repeatedly advances its
position in one direction while indefinitely repeating the same state.
In C terms, there is no real world output device that can hold the
output of `while (1) putchar('x');`.
It's the unboundedness of the tape that makes the halting problem
unsolvable. It's what allows the combined internal (finite state)
and external (unbounded tape) state of a TM to be unbounded. If we
considered only TMs that consume less than N tape cells, for any
finite N, the halting problem *for such TMs* would be theoretically
solvable by detecting or not detecting a repeated state.
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */
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How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-14 13:13 +0800
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 07:02 +0100
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-14 09:51 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 00:43 +0800
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 18:14 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 01:33 +0800
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 18:49 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 02:01 +0800
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 19:38 +0100
Re: How to write a self-referencial TM? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-14 13:00 -0700
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-14 15:02 -0500
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 21:19 +0100
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 21:16 +0100
Re: How to write a self-referencial TM? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-14 13:49 -0700
Re: How to write a self-referencial TM? Mr Flibble <flibble@red-dwarf.jmc.corp> - 2025-05-14 21:13 +0000
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-15 10:24 +0300
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 22:28 +0100
Re: How to write a self-referencial TM? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-14 14:40 -0700
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-14 23:02 +0100
Re: How to write a self-referencial TM? Andy Walker <anw@cuboid.co.uk> - 2025-05-15 01:09 +0100
Re: How to write a self-referencial TM? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2025-05-14 17:19 -0700
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 09:38 +0800
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 09:58 +0800
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 10:11 +0800
Re: How to write a self-referencial TM? Ben Bacarisse <ben@bsb.me.uk> - 2025-05-15 00:55 +0100
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-15 10:17 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-14 12:24 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 01:39 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-14 12:45 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 02:13 +0800
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-15 01:53 +0800
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-15 17:08 +0100
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-15 11:47 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-16 03:57 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-15 15:50 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-16 10:33 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 10:43 -0500
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-16 12:10 -0400
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-17 11:58 +0300
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-15 19:37 -0400
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-16 10:27 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 10:40 -0500
Re: How to write a self-referencial TM? "Fred. Zwarts" <F.Zwarts@HetNet.nl> - 2025-05-19 10:21 +0200
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-19 13:39 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-20 23:41 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-21 11:47 +0300
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-21 07:11 -0400
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-16 02:49 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-15 14:15 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-16 04:08 +0800
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-16 10:45 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 10:47 -0500
Re: How to write a self-referencial TM? "Fred. Zwarts" <F.Zwarts@HetNet.nl> - 2025-05-16 21:34 +0200
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-16 10:40 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 10:44 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-17 12:02 +0300
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-16 01:40 +0100
Re: How to write a self-referencial TM? Richard Heathfield <rjh@cpax.org.uk> - 2025-05-16 01:59 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-16 09:47 +0800
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-16 03:26 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-16 19:40 +0800
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-16 16:33 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-17 03:35 +0800
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-16 23:51 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-17 11:01 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 22:12 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-17 11:23 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 22:40 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-17 11:49 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 22:58 -0500
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-17 09:02 -0400
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-17 15:45 +0100
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-18 03:26 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-17 14:39 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-18 11:20 +0300
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-19 04:35 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-18 15:57 -0500
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-18 17:45 -0400
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-19 05:46 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-18 17:09 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-19 06:35 +0800
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-18 19:09 -0400
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-19 07:54 +0800
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-19 13:52 +0300
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-19 13:48 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-20 23:36 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-21 11:56 +0300
Re: How to write a self-referencial TM? André G. Isaak <agisaak@gm.invalid> - 2025-05-18 15:58 -0600
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-18 17:08 -0500
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-18 19:19 -0400
Re: How to write a self-referencial TM? André G. Isaak <agisaak@gm.invalid> - 2025-05-18 21:21 -0600
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-18 23:07 -0500
Re: How to write a self-referencial TM? "Fred. Zwarts" <F.Zwarts@HetNet.nl> - 2025-05-19 09:54 +0200
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-19 15:29 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-20 23:33 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-21 12:03 +0300
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-21 07:16 -0400
Re: How to write a self-referencial TM? "Fred. Zwarts" <F.Zwarts@HetNet.nl> - 2025-05-21 21:43 +0200
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-21 14:49 -0500
Re: How to write a self-referencial TM? "Fred. Zwarts" <F.Zwarts@HetNet.nl> - 2025-05-23 13:03 +0200
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-19 13:44 +0300
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-19 13:41 +0300
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-17 20:46 +0100
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-17 14:55 -0500
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-17 16:07 -0400
Re: How to write a self-referencial TM? Andy Walker <anw@cuboid.co.uk> - 2025-05-16 12:22 +0100
Re: How to write a self-referencial TM? Mike Terry <news.dead.person.stones@darjeeling.plus.com> - 2025-05-16 16:57 +0100
Re: How to write a self-referencial TM? Andy Walker <anw@cuboid.co.uk> - 2025-05-16 21:04 +0100
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 15:38 -0500
Re: How to write a self-referencial TM? wij <wyniijj5@gmail.com> - 2025-05-17 05:21 +0800
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 16:40 -0500
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-16 20:32 -0400
Re: How to write a self-referencial TM? Richard Damon <richard@damon-family.org> - 2025-05-16 17:59 -0400
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-16 10:24 +0300
Re: How to write a self-referencial TM? olcott <polcott333@gmail.com> - 2025-05-16 10:37 -0500
Re: How to write a self-referencial TM? Mikko <mikko.levanto@iki.fi> - 2025-05-15 10:07 +0300
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