Game Theory 101 (#66): Ex Ante and Interim Dominance

While dominance is straightforward in complete information games, incomplete information complicates matters. This lecture explains the two different types of dominance in Bayesian games: ex ante dominance and interim dominance. Ex ante dominance focuses on the strategies of a player (before he has learned of his type) while interim dominance focuses on the strategies of a type. Interim dominance implies ex ante dominance but not vice versa. As with complete information games, you should immediately eliminate any strictly dominated strategies, regardless of whether they are ex ante or interim dominated. Eliminating weakly dominated strategies can remove Bayesian Nash equilibria, so you still need to be careful with that..

game theory,   bayesian nash equilibrium,   incomplete information,   dominance,   strict dominance,   weak dominance,   ex ante dominance,   interim dominance,   lecture,   class,   tutorial