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From: lhe@sicsten.UUCP
Newsgroups: net.lang.prolog
Subject: Re: Standard behavior? (semantics of nonlogical primitives)
Message-ID: <1169@sicsten.UUCP>
Date: Thu, 12-Jun-86 22:01:02 EDT
Article-I.D.: sicsten.1169
Posted: Thu Jun 12 22:01:02 1986
Date-Received: Tue, 17-Jun-86 09:01:16 EDT
References: <980@watdragon.UUCP> <253@ubc-cs.UUCP> <1021@watdragon.UUCP> <1163@sicsten.UUCP> <127@sbcs.UUCP>
Reply-To: lhe@sicsten.UUCP (Lars-Henrik Eriksson)
Organization: Swedish Institute of Computer Science
Lines: 18

In article <127@sbcs.UUCP> debray@sbcs.UUCP writes:
>...
>Perhaps you mean "... cannot be described logically using first order
>predicate calculus".  

I did. The posting I responded to talked about "cut" etc. as being "described
logically". I understood this as meaning "defined in pure Prolog" (or
in first order predicate calculus), whis is not possible. Certainly you can
define things like "var" using other nonlogical constructs.

>If the constructs are in any way "understandable", you ought to be able to
>find mathematical models for them.  In the case of "cut", "var" etc. there's
>a good chance these won't look like the Herbrand models we Prolog hackers are
>accustomed to, of course, but that's rather different from saying that they
>couldn't be given any meaning at all.
>...

I agree completely.