Disjunctive Logic Programs with Inheritance DBAI-TR-99-30

The paper proposes a new knowledge representation language , c lledDLP<, which extends disjunctive logic programming (with strong negati on) by inheritance. The addition of inheritance enhances the knowledge modeling features of the lang uage providing a natural representation of default reasoning with exceptions. A declarative model-theoretic semantics of DLP< is provided, which is shown to generalize the answer set semantics of disjunctive logic programs. The knowledge modeling features of the language are illustr ated by encoding classical nonmonotonic problems inDLP<. The complexity ofDLP< is analyzed, proving that inheritance does not cause any com putational overhead, as reasoning in DLP< has exactly the same complexity as reasoning in disjunctive logic programming. This is confirmed by the existence of an efficien t translation fromDLP< to plain disjunctive logic programming. Using this translation, an adv nced KR system supporting the DLP< language has been implemented on top of the dlv system.