From jdering@asz-home.nl  Wed Jun 16 18:29:17 1999
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Date: Wed, 16 Jun 1999 18:29:34 +0200
To: <prolog@swi.psy.uva.nl>
From: Koos Dering <jdering@asz-home.nl>
Subject: RE/Help
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>
>I try to write a simple program to define a plus by myself. 
>
>sum(X,0,X).
>sum(W, f(Y), f(Z)):-sum(W,Y,Z).
>
>This doesnot work and just keep telling me to refine sum.
>Please tell me the reason.
>
>The goal of this program is to define sum(X,Y,Z) : Z=X+Y,
>Not by using the build_in predictors, such as plus or is.
>
>Thank you 
>
>
(with reference to Steffens RE)
even your original version seems to work admirably so it might be useful to
quote the actual input to - and output of the system.


