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Article #204Re: To all who posted supposedly solutions of J.W. Lloyds example
From: enrico
Date: Wed, 15 Apr 1992 15:29
Date: Wed, 15 Apr 1992 15:29
34 lines
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1377 bytes
In article <3729@tuegate.tue.nl> wsbusup4@rwa.urc.tue.nl (Jan Stout) writes: > > You all assume that :- means logical equivalence, i.e. <->, but I was taught > that it means logical consequence, i.e. <-. > > Surely the :- looks more like an <- than like a <->. I was even told that > the :- was designed to look like the --in most charactersets absent-- > \leftarrow symbol. > > Jan Stout. Yes, you are correct saying that :- means <-, but you must remember that by definition when you construct the completion of a program P (Comp(P)) you transform the implications in logical equivalences; that is if you have a definition for a predicate p p :- q1 ... p :- qn then in Comp(P) you will have p <-> (q1 v ... v qn) (modulo the usual quantifications....) Ciao Enrico ------------------------- Pontelli Enrico University of Houston Dept. Computer Science
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Newsgroups: comp.lang.prolog Path: arc1-ca.pugleaf.net!sparky!uunet!zaphod.mps.ohio-state.edu!menudo.uh.edu!usenet From: enrico@cs.uh.edu Subject: Re: To all who posted supposedly solutions of J.W. Lloyds example Message-ID: <1992Apr15.152958.17881@menudo.uh.edu> Sender: usenet@menudo.uh.edu (USENET News System) Nntp-Posting-Host: alpha.cs.uh.edu Organization: University of Houston References: <3729@tuegate.tue.nl> Date: Wed, 15 Apr 1992 15:29:58 GMT Lines: 34