This paper focuses on implementation issues in environments where it may be costly for the players to send certain messages. We develop an approach allowing to characterize the set of implementable outcomes in such environments, and then apply it to derive optimal mechanisms. The key elements of...

Technical supplement to the paper forthcoming in Rand Journal of Economics.

We study implementation in environments where agents have limited ability to imitate others. Agents are randomly and privately endowed with type-dependent sets of messages. So sending a message becomes a partial proof regarding type. For environments where agents can send any combination of...