In two-sided matching markets in which some doctors form couples, we present an algorithm that finds all the stable matchings whenever one exists, and otherwise shows that there is no stable matching. Extending the methodology of Echenique and Yenmez (2006), we characterize the set of stable matchings as the fixed points of a monotone decreasing function with respect to a certain partial order....

In this paper I study the strategic implications of coalition formation in an assembly. A coalition forms a voting bloc to coordinate the voting behavior of its members, acting as a single player and affecting the policy outcome. In a game of endogenous coalition formation, I show that voting blocs form in equilibrium, and in an assembly with two parties I show how the incentives to join a bloc...

In an infinite-horizon setting, Ferejohn and Page showed that Arrow’s axioms and stationarity lead to a dictatorship by the first generation. Packel strengthened this result by proving that no collective choice rule generating complete social preferences can satisfy unlimited domain, weak Pareto and stationarity. We prove that a domain restriction can be imposed and completeness can be dropped ...

Game theory traditionally specifies players’ numerical payoff functions. Following the concept of utility invariance in modern social choice theory, this paper explores what is implied by specifying equivalence classes of utility function profiles instead. Within a single game, utility transformations that depend on other players’ strategies preserve players’ preferences over their own strategi...

We investigate the adverse selection problem where a principal delegates multiple tasks to an agent. We characterize the virtually implementable social choice functions by using the linking mechanism proposed by Jackson and Sonnenschein (2007) that restricts the message spaces. The principal does not require any incentive wage schemes and can therefore avoid any information rent and welfare los...

We consider the problem of ranking sets of objects, the members of which are mutually compatible. Assuming that each object is either good or bad, we axiomatically characterize three cardinality-based rules which arise naturally in this dichotomous setting. They are what we call the symmetric difference rule, the lexicographic good-bad rule, and the lexicographic bad-good rule. Each of these ru...

We consider envy-free and budget-balanced allocation rules for problems where a number of indivisible objects and a fixed amount of money is allocated among a group of agents. In “small” economies, we identify under classical preferences each agent’s maximal gain from manipulation. Using this result we find the envy-free and budget-balanced allocation rules which are least manipulable for each ...

We prove a general possibility result for collective decision problems where individual allocations are one-dimensional, preferences are single-peaked (strictly convex), and feasible allocation profiles cover a closed convex set. Special cases include the celebrated median voter theorem ([10], [21]) and the division of a non disposable commodity by the uniform rationing rule ([47]). We construc...

Who Is the Enemy? We examine who benefits when there is a strong leader in place, and those who benefit when a situation lacks a proper leader. There are fractious terrorist groups who seek to serve the same people in common cause against a common enemy. The groups compete for rents obtained from the public by engaging in actions against the common enemy. We derive a condition under which the c...

This article reviews recent developments in the theory of committee decisionmaking. A committee consists of self-interested members that make a public decision by aggregating imperfect information dispersed among them according to a pre-specified decision rule. We focus on costly information acquisition, strategic information aggregation, and rules and processes that enhance the quality of the ...