Newsgroups: comp.lang.prolog
Path: cantaloupe.srv.cs.cmu.edu!rochester!udel!gatech!howland.reston.ans.net!Germany.EU.net!Munich.Germany.EU.net!ecrc!acrab60!thom
From: thom@ecrc.de (Thom Fruehwirth)
Subject: Re: Representing Mutual Exclusion in Prolog
Message-ID: <D7quJF.M3I@ecrc.de>
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Organization: European Computer-Industry Research Centre GmbH.
References: <3n6cqm$ofs@mozo.cc.purdue.edu>
Date: Fri, 28 Apr 1995 11:57:15 GMT
Lines: 13

Randall A Helzerman wrote on April 20:

   Is there anyway in prolog that I can represent two mutually-exclusive
   (possibly non-ground) atoms?  Theoretically, something like

   <empty clause> :- a(X), not_a(X).

With constraint handling rules you would write this as:

 a(X),not_a(X) ==> fail.

thom

