Answer Sets and Qualitative Decision Making

Logic programs under answer set semantics have become popular as a knowledge representation formalism in Artificial Intelligence. In this paper we investigate the possibility of using answer sets for qualitative decision making. Our approach is based on an extension of the formalism, called logic programs with ordered disjunction ( LPOD s). These programs contain a new connective called ordered disjunction. The new connective allows us to represent alternative, ranked options for problem solutions in the heads of rules: A × B intuitively means: if possible A , but if A is not possible then at least B . The semantics of logic programs with ordered disjunction is based on a preference relation on answer sets. We show that LPOD s can serve as a basis for qualitative decision making.