In a large economy, a first-best provison rule for a public good is robustly implementable with budget balance because no one individual alone can affect the aggregate outcome. First-best outcomes can, however, be blocked by coalitions of agents acting in concert. With a requirement of immunity...

The paper considers a voting model where each voter's type is her preference. The type graph for a voter is a graph whose vertices are the possible types of the voter. Two vertices are connected by an edge in the graph if the associated types are "neighbors." A social choice function is locally...

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...