The paper studies the implementation problem, first analyzed by Maskin and Moore (1999), in which two agents observe an unverifiable state of nature and may renegotiate inefficient outcomes following play of the mechanism. We develop a first-order approach to characterizing the set of...

We consider Bayesian incentive-compatible mechanisms with independent types and either private values or interdependent values that satisfy a form of "congruence." We show that in these settings, interim participation constraints are satisfied when the status quo is the randomized allocation...