From kalvala  Wed May 23 10:48:58 1990
Received: by iris.ucdavis.edu (5.57/UCD.EECS.2.0)
        id AA21703; Wed, 23 May 90 10:48:58 PDT
Message-Id: <9005231748.AA21703@iris.ucdavis.edu>
To: info-hol
Subject: Recursion in HOL
Date: Wed, 23 May 90 10:48:51 PDT
From: sara kalvala <kalvala>


I wanted to play with recursive definitions in HOL, and decided that a
specification for GCD would be a good start. Here's what I want:

     GCD 0 b = b /\
     GCD a b = ((a < b) => (GCD (b-a) a)
                         | (GCD (a-b) b))

This seems much harder than I thought - I don't know if the main
problem is with having recursion over a *pair* of numbers or with the
fact that it does not involve a clear "successor" relation.

Any insights into this?

                                                        - Sara Kalvala
                                                kalvala@iris.ucdavis.edu


