A mechanism implements a social choice correspondence f in mixed Nash equilibrium if at any preference profile, the set of all pure and mixed Nash equilibriumoutcomes coincides with the set of f-optimal alternatives at that preference profile. This definition generalizes Maskin’s definition of...

We study the repeated implementation of social choice functions in environments with complete information and changing preferences. We de?ne dynamic mono- tonicity, a natural but nontrivial dynamic extension of Maskin monotonicity, and show that it is necessary and almost suf?cient for repeated...