A Non-monotonic Logic for Specifying and Querying Preferences

Guido Boella, Leendert W. N. van der Torre

Abstract: Preferences are becoming of greater interest in many areas of artificial intelligence, such as knowledge representation, multiagent systems, constraint satisfaction, decision making, and decision-theoretic planning. In the logic of preference there is a debate when a set of preferences should be consistent. For example, Bacchus and Grove [1996] criticize ceteris paribus preferences, because {p > ¬p,¬p ∧ q > p ∧ q} should be consistent, and they criticize most existing logics of preference, because {p > ¬p, q > ¬q,¬(p∧ q) > p∧ q} should be consistent. In order not to restrict the use of the logic of preference, we propose a minimal logic of preference in which any set of specified preferences is consistent. To make it useful for practical applications, we extend this logic to specify preferences with a logic to query preferences, and with a nonmonotonic reasoning mechanism.