We provide a characterization of virtual Bayesian implementation in pure strategies for environments satisfying no-total-indifference. A social choice function in such environments is virtually Bayesian implementable if and only if it satisfies incentive compatibility and a condition we term...

This paper provides a general overview of the literature on the core of an exchange economy with asymmetric information. Incentive compatibility is emphasized in studying core concepts at the ex ante and interim stage. The analysis includes issues of non-emptiness of the core as well as core...

In a differencial economy with quasi-linear utilities, monetary transfers facilitate the fulfilment of incentive compability constraints: the associated ex ante core is generically nonempty. However, we exhibit a well-behaved exchange economy in which this core is empty, even if goods are...

An appropriate (interim) notion of the core for an economy with incomplete information depends on the amount of information that coalitions can share. The coarse and fine core, as originally defined by Wilson (1978), correspond to two polar cases, involving no information sharing and arbitrary...

It is well known that a social choice function is truthfully implementable in Bayesian Nash equilibrium if and only if it is incentive compatible. However, in general it is not possible to rule out other equilibrium outcomes, and additional conditions, e.g., Bayesian monotonicity, are needed to...

An appropriate (interim) notion of the core for an economy with incomplete information depends on the amount of information that coalitions can share. The coarse and fine core, as originally defined by Wilson (1978), correspond to two polar cases, involving no information sharing and arbitrary...

A core allocation of a complete information economy can be characterized as one that would not be unanimously rejected in favor of another feasible alternative by any coalition. We use this test of coalitional voting in an incomplete information environment to formalize a notion of resilience....

We provide a mechanism that approximately implements the Mas-Colell bargaining set in subgame perfect equilibrium. The mechanism is based on the definition of the Mas-Colell bargaining set, and respects feasibility in and out of equilibrium.

Harsanyi (1974) criticized the von Neumann-Morgenstern notion of a stable set on the grounds that it implicitly assumes coalitions to be shortsighted in evaluating their prospects. He proposed a modification of the dominance relation to incorporate farsightedness. In doing so, however, Harsanyi...

This chapter surveys the sizable and growing literature on coalition formation. We refer to theories in which one or more groups of agents (“coalitions”) deliberately get together to jointly determine their actions. The defining idea of a coalition, in this chapter, is that of a group which...