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- Path: sparky!uunet!pipex!bnr.co.uk!uknet!glasgow!jack
- From: jack@dcs.glasgow.ac.uk (Jack Campin)
- Newsgroups: comp.theory
- Subject: Re: Real Numbers vs. Rational Numbers?
- Message-ID: <BzMGIy.D39@dcs.glasgow.ac.uk>
- Date: 21 Dec 92 18:25:45 GMT
- References: <1992Dec16.095412.19570@tom.rz.uni-passau.de> <7111@tivoli.UUCP>
- Reply-To: jack@dcs.glasgow.ac.uk (Jack Campin)
- Organization: COMANDOS Project, Glesga Yoonie
- Lines: 31
-
- taylor@foraker.NoSubdomain.NoDomain (Eric Taylor) wrote:
- > boerncke@kirk.fmi.uni-passau.de (Frank-Roland Boernke) writes:
- >> Our professor told us, that RAMs are allowed to store REAL numbers too AND
- >> they are still as powerful as an ordinary turing machine. I claimed, this
- >> can`t be true, since there isn`t any possibility to work with irrational
- >> numbers in TMs.
- > REAL numbers are always RATIONAL numbers and vice-versa. The terminology
- > "REAL number", I believe, is not a formal one, but one borrowed from
- > something like FORTRAN where they are simply meant to represent floating
- > point numbers. Any rational number can be represented by the division of
- > 2 integers and are therefore easily handled by a RAM or Turing machine.
-
- I think I'll have that one bronzed. You'll be a *long*, *long* time living
- that one down, pal. Count yourself lucky that the trained ape who did your
- news configuration has preserved you some measure of anonymity by obscuring
- your site's identity.
-
- Anyone else tempted to add their own bladderful to this torrent of
- misinformation: there is a substantial literature on computing with real
- numbers, ultimately going all the way to Brouwer's intuitionism of the
- 1920s, and you will look less of an idiot than these two if you read some
- of it. For starters you might get a copy of Lecture Notes in Computer
- Science 613, "Constructivity in Computer Science", ed. J.P. Myers and M.J.
- O'Donnell, Springer-Verlag 1991, and read back from the references in the
- Chirimar/Howe, Tucker/Zucker, and Weihrauch papers there.
-
- --
- -- Jack Campin room G092, Computing Science Department, Glasgow University,
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