The paper describes an extension of well-founded semantics for logic programs with two types of negation. In this extension information about preferences between rules can be expressed in the logical language and derived dynamically. This is achieved by using a reserved predicate symbol and a naming technique. Con icts among rules are resolved whenever possible on the basis of derived preference information. The well-founded conclusions of prioritized logic programs can be computed in polynomial time. A legal reasoning example illustrates the usefulness of the approach.
In the article REF , one of the authors of the present paper has described a prioritized version of the well-founded semantics for extended logic programs.
Well-Founded Semantics for Extended Logic Programs with Dynamic Preferences
Journal of Artificial Intelligence Research, Vol 4, (1996), 19-36
Computer Science Mathematics