Disjunctive logic programs and constraint processing

Abstract

In this paper, we extend the semantics of extended Horn programs to disjunctive logic programs with classical negation. We call such programs as extended disjunctive logic programs. We show that the extension allows certain type of conclusions to be inferred which are not possible with disjunctive programs. We also develop declarative and procedural semantics for inferring from extended disjunctive logic programs. Next, we use extended disjunctive logic programs to deal with default reasoning, in the form of rules and integrity constraints. Disjunctive program clauses with negative conclusions are viewed as constraints which constrain the inference that can be made from the disjunctive program clauses with positive conclusions. Whenever a conclusion from the program violates an integrity constraint, then that conclusion is not allowed to be made. We develop a declarative semantics and define a proof procedure for constraint processing with disjunctive logic programs.