A social choice rule (SCR) $F$ maps preference profiles to lotteries over some finite set of outcomes. $F$ is virtually implementable in (pure and mixed) Nash equilibria provided that for all $\epsilon 0$, there exists a mechanism such that for each preference profile $\theta$, its set of Nash...

In this paper, we re-examine the classical questions of implementation theory under complete information in a setting where coalitions are the fundamental behavioral units and the outcomes of their interactions are predicted by applying the solution concept of the core. The planner's exercise...

We study necessary and sufficient conditions for a multi-valued solution S to be rationalized in the following sense: there exists a complete asymmetric relation T (a tournament) such that, for each feasible (finite) set, the solution set of S coincides with the minimal covering set of T...

A reason-based choice correspondence rationalizes choice behaviour in terms of a two-stage choice procedure. Given a feasible set S, the individual eliminates from it all of the dominated alternatives according to her fixed (not necessarily complete) strict preference relation, in the first...

We study necessary and sufficient conditions for a choice function to be rationalised in the following sense: there exists a complete asymmetric relation T (a tournament) such that for each feasible (finite) choice situation, the choice coincides with the uncovered set of T restricted to that...

Consider a society with two sectors (issues or objects) that faces a design problem. Suppose that the sector-2 dimension of the design problem is fixed and represented by a mechanism Γ², and that the designer operates under this constraint for institutional reasons. A sector-1 mechanism Γ¹...

Consider a society with a finite number of sectors (social issues or commodities). In a partial equilibrium (PE) mechanism a sector authority (SA) aims to elicit agents' preference rankings for outcomes at hand, presuming separability of preferences, while such presumption is false in general...

The paper proposes necessary and sufficient conditions for the natural implementation of (efficient) social choice correspondences (SCCs) in pure finite exchange economies when some of the agents are partially honest. A partially honest agent is an agent who strictly prefers to tell the truth...

An individual may display an honesty standard which allows her to lie a little without that being harmful to her self view as an honest person. On this basis, the paper considers a society with a finite number of individuals involving partially-honest individuals and in which every individual...

We study the relationship between two-agent implementation problems and the notionof interim efficiency due to Holmström and Myerson (1983) in Bayesian environmentswith private values and independent types. We present a general property, Bayesianefficiency, and show that it is sufficient for...