LPOD Answer Sets and Nash Equilibria

Logic programs with ordered disjunctions (LPODs) are natural vehicles for expressing choices that have a preference ordering. They are extensions of the familiar extended logic programs that have answer sets as semantics. In game theory, players usually prefer strategies that yield higher payoffs. Since strategies are choices, LPODs would seem to be a suitable logical formalism for expressing some game-theoretic properties. This paper shows how pure strategy normal form games can be encoded as LPODs in such a way that the answer sets that are mutually most preferred by all players are exactly the Nash equilibria. A similar result has been obtained by researchers using a different, but related, logical formalism, viz., ordered choice logic programs that were used to encode extensive games.