Repeated implementation with overlapping generations of agents

We study repeated implementation in a model with overlapping generations of agents. A social choice function selects an alternative in each period as a function of preferences of those agents who are alive in that period. When the agents’ preferences do not change during their lifetime, we show that any social choice function satisfying a mild unanimity condition is repeatedly implementable in subgame perfect equilibrium if there are at least three agents and they live sufficiently long. When the agents’ preferences change every period, we show that only efficient social choice functions can be repeatedly implementable if the agents live sufficiently long