Compromise by "multimatum"

Abstract: We propose a solution and a mechanism for two-agent social choice problems with large (infinite) policy spaces. Our solution is an efficient compromise rule between the two agents, built on a common cardinalization of their preferences. Our mechanism, the \emph{multimatum} has the two players alternate in proposing sets of alternatives from which the other must choose. Our main result shows that the multimatum fully implements our compromise solution in subgame perfect Nash equilibrium. \ We demonstrate the power and versatility of this approach through applications to political economy, other-regarding preferences, and facility location.