We study a multi-dimensional collective decision under incomplete information. Agents have Euclidean preferences and vote by simple majority on each issue (dimension), yielding the coordinate-wise median. Judicious rotations of the orthogonal axes -- the issues that are voted upon -- lead to...

In this paper, we show that in pure exchange economies where the number of goods equals or exceeds the number of agents, any Pareto-efficient and strategy-proof allocation mechanism always allocates the total endowment to some single agent even if the receivers vary.

Why do rational politicians choose inefficient policy instruments? Environmental regulation, for example, often takes the form of technology standards and quotas even when cost-effective Pigou taxes are available. To shed light on this puzzle, we present a stochastic game with multiple...

We study collective choice via an endogenous agenda setting process. At each stage, a status quo is implemented unless it is replaced by a majority (winning coalition) with a new status quo outcome. The process continues until the prevailing status quo is no longer challenged. We impose a...

In a voting model where the set of feasible alternatives is a subset of a product set $A = A_1\times\cdots\ldots{}A_m$ of $m$ finite categories, we characterize the set of all strategy-proof social choice functions for three different types of preference domains over $A$, namely for the domains...

We generalize the canonical problem of Nash implementation by allowing agents to voluntarily provide discriminatory signals, i.e. evidence. Evidence can either take the form of hard information or, more generally, have differential but non-prohibitive costs in different states. In such...

We consider a (pure) public goods provision problem with voluntary participation in a quasi-linear economy. We propose a new hybrid solution concept, the free-riding-proof core (FRP-Core), which endogenously determines a contribution group, public goods provision level, and how to share the...

We study the possibilities for agenda manipulation under strategic voting for two prominent sequential voting procedures: the amendment procedure and the suc- cessive procedure. We show that a well known result for tournaments, namely that the successive procedure is (weakly) more manipulable...

Group identification refers to the problem of classifying individuals into groups (e.g., racial or ethnic classification). We consider a multinary group identification model where memberships to three or more groups are simultaneously determined based on individual opinions on who belong to what...

This paper studies how electoral incentives influence the outcomes of political negotiations. It considers a game between two political parties that have to bargain over which policy to implement. While bargaining, the parties' popularity varies over time. Changes in popularity are partly...