Under consideration for publication in Theory and Practice of Logic Programming 1 Disjunctive Logic Programs with Inheritance

The paper proposes a new knowledge representation language, called�ÄÈ�, which extends disjunctive logic programming (with strong negation) by inheritance. The addition of inheritance enhances the knowledge modeling features of the language providing a natural representation of default reasoning with exceptions. A declarative model-theoretic semantics of�ÄÈ�is provided, which is shown to generalize the Answer Set Semantics of disjunctive logic programs. The knowledge modeling features of the language are illustrated by encoding classical nonmonotonic problems in�ÄÈ�. The complexity of�ÄÈ�is analyzed, proving that inheritance does not cause any computational overhead, as reasoning in�ÄÈ�has exactly the same complexity as reasoning in disjunctive logic programming. This is confirmed by the existence of an efficient translation from�ÄÈ�to dis-the�ÄÈ� plain junctive logic programming. Using this translation, an advanced KR system supporting language has been implemented on top of the DLV system and has subsequently been integrated into DLV.