From dazy@cnam.fr  Mon Nov 27 11:21:57 2000
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Date: Mon, 27 Nov 2000 11:23:43 +0100
From: "jean-F. Dazy" <dazy@cnam.fr>
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To: prolog@swi.psy.uva.nl, "dazy@cnam.fr" <dazy@cnam.fr>
Subject: not with trace  or not with fail ???
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?- not(v).
ERROR: Undefined procedure: v/0


?- unknown(_ , fail).
Yes
?- not(v).

Yes

it is dangerous  !
2 differents semantics ????

jfd



