In the standard principal-supervisor-agent model with collusion, Tirole (1986) shows that employing a supervisor is profitable for the principal if the supervisor's signal of the agent's cost of production is 'hard' (i.e., verifiable but hideable). Anecdotal evidence suggests that information is...

We study the implementation problem for exchange economies when agents can renegotiate the outcome assigned by the planner and can collude. We focus on the use of sequential mechanisms and present a simple sufficient condition for implementation with renegotiation in strong perfect equilibrium....