Article View: comp.theory
Article #1723Real Numbers vs. Rational Numbers?
From: Frank-Roland Boernke
Date: Wed, 16 Dec 1992 09:54
Date: Wed, 16 Dec 1992 09:54
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1762 bytes
In lectures we talked about the RAM, a formal machine-model that is proved to be as powerful as turing-machines(TM) and vice versa, according to the Church-Turing-Thesis. This seems to be ok until you say, that the RAM allows only natural numbers in its registers (or rational-numbers, since they are countable). 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. Of course, e.g. you can compute Pi up to as many digits as you want, but in every step of computation you only have an approximation - a rational number. Therefore, a machine-model, that allows real numbers, must be more powerful than another one that does not. My professor said, that isn`t a problem but I don`t agree. Who is right? If I am wrong, please let me know where the fault is. Thanks in advance. ------------------------------------------------------------------------- Frank Boerncke ,,, University of Passau - Germany boerncke@kirk.fmi.uni-passau.de (.~.) phone: +49 0851 2267 --------------------------------oOO--(_)--OOo---------------------------
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Newsgroups: comp.theory Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!Germany.EU.net!math.fu-berlin.de!informatik.tu-muenchen.de!rz.uni-passau.de!kirk.fmi.uni-passau.de!boerncke From: boerncke@kirk.fmi.uni-passau.de (Frank-Roland Boernke) Subject: Real Numbers vs. Rational Numbers? Message-ID: <1992Dec16.095412.19570@tom.rz.uni-passau.de> Sender: news@tom.rz.uni-passau.de (News-Operator) Organization: University of Passau, Germany Date: Wed, 16 Dec 1992 09:54:12 GMT Lines: 26