We give a family of dictatorship tests with perfect completeness and low-soundness for 2–to–2 constraints. The associated 2–to–2 conjecture has been the basis of some previous inapproximability results with perfect completeness. However, evidence towards the conjecture in the form of integrality gaps even against weak semidefinite programs has been elusive. Our result provides some indication o...

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 ...

Fix a Pareto optimal, strategy proof and non-bossy deterministic matching mechanism and define a random matching mechanism by assigning agents to the roles in the mechanism via a uniform lottery. Given a profile of preferences, the lottery over outcomes that arises under the random matching mechanism is identical to the lottery that arises under random serial dictatorship, where the order of di...

We study two-sided many-to-one matching markets with interdependent valuations and imperfect information held by one side of the market. The other side has common and known preferences over potential mates. In this setting, pairwise stability does not imply group stability: mechanisms that are stable with respect to deviations by pairs of agents may be vulnerable to deviations by groups. We for...

We study the truthful facility assignment problem, where a set of agents with private most-preferred points on a metric space are assigned to facilities that lie on the metric space, under capacity constraints on the facilities. The goal is to produce such an assignment that minimizes the social cost, i.e., the total distance between the most-preferred points of the agents and their correspondi...