We study what kind of equilibria of which mechanisms are ex post renegotiation-proof (EPRP), i.e., robust against the possibility of ex post renegotiation under a variety of renegotiation procedures, and which social choice functions are EPRP implementable. In complete information environments...

We study a contract design setting in which the contracting parties cannot commit not to renegotiate previous contract agreements. In particular, we characterize the outcome functions that are implementable for an uninformed principal and an informed agent if, having observed the agent's...

In a class of informed principal problems with common values, we define iteratively a particular allocation which we call the assured allocation. It is comparatively easy to calculate and straightforward to interpret. It always exists, is unique and continuous in the priors. It is undominated,...

This paper characterizes the set of equilibrium payoffs in bargaining with interdependent values when the informed party makes all offers, as discounting vanishes. The seller of a good is informed of its quality, which affects both his cost and the buyer's valuation, but the buyer is not. To...

We uncover a new necessary condition for implementation in iteratively undominated strategies by mechanisms that satisfy the “best element property” where for each agent, there exists a strategy profile that gives him the highest payoff in the mechanism. This class includes finite and...

We characterize the boundaries of the set of transfers (extremal transfers) implementing a given allocation rule without imposing any assumptions on the agentʼs type space or utility function besides quasi-linearity. Exploiting the concept of extremal transfers allows us to obtain an exact...

In this paper, we examine the optimal mechanism design of selling an indivisible object to one regular buyer and one publicly known buyer, where inter-buyer resale cannot be prohibited. The resale market is modeled as a stochastic ultimatum bargaining game between the two buyers. We fully...

This paper studies optimal auction design when the seller can affect the buyersʼ valuations through an unobservable ex ante investment. The key insight is that the optimal mechanism may have the seller play a mixed investment strategy so as to create correlation between the buyersʼ otherwise...

We study a mechanism design problem where arbitrary restrictions are placed on the sets of first-order beliefs of agents. Calling these restrictions Δ, we use Δ-rationalizability (Battigalli and Siniscalchi, 2003, [5]) as our solution concept, and require that a mechanism virtually implement a...

This paper investigates optimal mechanisms in a principal–agent framework with a two-dimensional decision space, quadratic payoffs and no monetary transfers. If the conflicts of interest between the principal and the agent are different on each dimension, then delegation is always strictly...