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- Newsgroups: comp.theory
- Path: sparky!uunet!munnari.oz.au!cs.mu.OZ.AU!aet
- From: aet@mullian.ee.mu.OZ.AU (bert thompson)
- Subject: Re: Real Numbers vs. Rational Numbers?
- Message-ID: <aet.725945425@munagin>
- Sender: news@cs.mu.OZ.AU
- Organization: Computer Science, University of Melbourne, Australia
- References: <1992Dec16.095412.19570@tom.rz.uni-passau.de> <1992Dec16.222628.27208@ringer.cs.utsa.edu> <1992Dec17.142150.7932@tom.rz.uni-passau.de> <1hi8dvINN5l2@uwm.edu>
- Distribution: inet
- Date: Sat, 2 Jan 1993 03:30:25 GMT
- Lines: 40
-
- markh@csd4.csd.uwm.edu (Mark) writes:
-
- >In article <1992Dec17.142150.7932@tom.rz.uni-passau.de> boerncke@kirk.fmi.uni-passau.de (Frank-Roland Boernke) writes:
- >>How is it possible to work with irrationals in a table? Of course you cannot store
- >>them digit by digit as there is an infinite number. But if you choose a finite
- >>representation e.g. two letters P and I for the sequence 3.141592654... how can
- >>you calculate say PI * PI?
-
- >Calculate PI * PI.
- >Answer: PI*PI.
-
- >Since "PI*PI" is a finite representation of PI * PI from which one can
- >algorithmically computer any of its digits in finite time, this counts as a
- >valid answer.
-
- >If you don't consider this valid, then neither will you consider this valid:
-
- >Calculate: 2 / 5
- >Answer: 2/5.
-
- >So then on that account, computers can't even work with fractions.
-
- In case you are interested in exact real arithmetic...
-
- Hans Boehm has written a simple calculator that performs arithmetic on
- constructive real numbers.
-
- his calculator is called C_calc.
-
- you can look it up on archie, or i can tell you where to get it.
-
- bert.
-
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- bert thompson aet@munagin.ee.mu.oz.au.
- SITEE school of information technology and electrical engineering
- university of melbourne
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- g e t t h e p o i n t
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-