sjb@cs.toronto.edu (Stephen Bellantoni) (08/28/89)
ACTIVITIES FOR THE WEEK COMMENCING SEPT 4
(SF = Sandford Fleming Building, 10 King's College Road)
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AI SEMINAR
SF1105, at 11:00 a.m., Thursday 7 September 1989
Dr. John Lloyd
University of Bristol
Updating Knowledge Bases
In this seminar, I consider the problem of updating a knowledge base, where
a knowledge base is realised as a logic program. In this general setting,
the update problem is as follows. Given an (arbitrary) program satisfying
an integrity constraint theory and a closed first order formula, which is
(resp., is not) a logical consequence of the completion of the program,
find a way to change the program so that the formula is no longer (resp.,
is) a logical consequence of the completion of the updated program and so
that the updated program also satisfies the integrity constraint theory. I
will present procedures for deleting an atom from a normal program and
inserting an atom into a normal program, concentrating particularly on the
case when negative literals appear in the bodies of program clauses. I will
also discuss various properties of the procedures including their
correctness.