PROLOG-REQUEST@SUSHI.STANFORD.EDU.UUCP (02/22/87)
PROLOG Digest Monday, 23 Feb 1987 Volume 5 : Issue 11
Today's Topics:
Query - Frames & Connection Graph Proof Procedure,
Programming - 91 Function
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From: "Norbert E. Fuchs" <fuchs%ifi.unizh.chunet@RELAY.CS.NET>
Subject: Frames in Prolog
Does anybody know about an efficient implementation of frames in
Prolog, or a Prolog system with frames?
Thank you very much for your help.
-- Norbert E. Fuchs
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Date: Tue, 17 Feb 87 19:11:37 est
From: Stephen Schaefer <schaefer%andy.bgsu.edu@RELAY.CS.NET>
Subject: Connection Graph Proof Procedure
Can anyone point me to further references on the application of the
connection graph proof procedure, described in Kowalski's _Logic_
_for_ _Problem_ _Solving_, chapter 8? Are any Prolog implementations
built on top of it? Thanks.
-- Stephen P. Schaefer
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Date: 17 Feb 87 23:21:17 GMT
From: milano!varghese@im4u.utexas.edu
Subject: 91 Function
In article <3782@milano.UUCP>, varghese@milano.UUCP writes:
>
> A "fix" to make it converge to 91:
>
> (defun f91 (x)
> (cond ((= x 91) 91)
> ((> x 111) (f91 (f91 (- x 10))))
> ((> x 100) (f91 (- x 10)))
> (t (f91 (f91 (+ x 11))))))
>
> or, if you don't speak LISP, a Prolog version:
>
> f91(91,91) :- !.
> f91(X,Y) :- X > 111, !, Z is X - 10, f91(Z,W), f91(W,Y).
> f91(X,Y) :- X > 100, !, Z is X - 10, f91(Z,Y).
> f91(X,Y) :- Z is X + 10, f91(Z,W), f91(W,Y).
>
The last line of the Prolog version should be
f91(X,Y) :- Z is X + 11, f91(Z,W), f91(W,Y).
to make it correspond to the Lisp version. I work on Lisp machines and
the Prolog version is a translation of the Lisp program. Sorry about
that.
-- Joe Varghese
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End of PROLOG Digest
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