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talk announcement Jim Delgrande
- From: Beatrix Forsthuber <firstname.lastname@example.org>
- Date: Wed, 24 Oct 2012 08:06:29 +0200
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The Database and Artificial Intelligence Group cordially invites you to the
Speaker: James Delgrande (joint work with Pavlos Peppas)
School of Computing Science
Simon Fraser University
Burnaby, B.C. Canada
DATE: Monday, 5. november 2012
VENUE: Seminarroom Gödel (Favoritenstrasse 9-11, ground floor)
TITLE: Revising Horn Theories
This talk addresses belief revision where the underlying logic is that
governing Horn clauses.
It proves to be the case that classical (AGM) belief revision doesn't
immediately generalise to the Horn case.
In particular, a standard construction based on a total preorder over
possible worlds may violate the accepted (AGM) postulates.
Conversely, Horn revision functions in the obvious extension to the AGM
approach are not captured by total preorders over possible worlds.
We address these difficulties by first restricting the semantic construction
to ``well behaved'' orderings;
and second, by augmenting the revision postulates by an additional postulate.
This additional postulate is redundant in the AGM approach but not in the
the Horn case.
In a representation result we show that these two approaches coincide.
Arguably this work is interesting for several reasons.
It extends AGM revision to inferentially-weaker Horn theories;
hence it sheds light on the theoretical underpinnings of belief change, as
well as generalising the AGM paradigm.
Thus, this work is relevant to revision in areas that employ Horn
clauses, such as deductive databases and logic programming, as well as areas
in which inference is weaker than classical logic, such as in description
With kind support of the Wolfgang Pauli Institut (WPI) and VCLA.
Institut für Informationssysteme E 184