The absence of simultaneous cycles is a sufficient condition for the existence of singleton cores. Acyclicity in the preferences of either side of the market is a minimal condition that guarantees the existence of singleton cores.

We provide a short proof for the following characterization of the core in housing markets first proved by Ma (1994): the core is the only rule that satisfies strategy-proofness, Pareto efficiency and individual rationality.

We provide a game-theoretic alternative of the kinked demand curve explanation of rigid prices. We analyze a duopoly where firms choose quantities and objectives. We identify cases under which firms choose to maximize their revenue. Under these cases, prices are insensitive to unit costs.

Recent research on the Condorcet Jury Theorem has proven that informative voting (that is, voting according to one’s signal) is not necessarily rational. With two alternatives, rational voting typically leads to the election of the correct alternative, in spite of the fact that not all voters...

An alternative is a Condorcet winner if it beats all other alternatives in a pairwise majority vote. A social choice correspondence is a Condorcet extension if it selects the Condorcet winners–and nothing else–whenever a Condorcet winner exists. It is well known that Condorcet extensions are...

We consider methods of electing a fixed number of candidates, greater than one, by approval ballot. We define a representativeness property and a Pareto property and show that these jointly imply manipulability.

This note provides an alternative derivation of the leximin principle using the framework of Harsanyi’s (1953) equi-probability model. We demonstrate that the leximin principle is concluded if and only if the preference ordering of the impartial observer obeys strong monotonicity and complete...

In this paper, virtual implementation is restricted to deliver, on the equilibrium path, either a socially optimal outcome or a status quo: an outcome fixed for all preference profiles. Under such a restriction, for any unanimous and implementable social choice function there is a dictator, who...

We provide conditions under which a Condorcet winner exists when voters are exogenously distributed in groups, with preferences satisfying the single-crossing property separately inside each group. We also show that the majority voting social preference is acyclic.

We consider an axiomatic characterization of the plurality rule, which selects the alternative(s) most preferred by the largest number of individuals. We strengthen the characterization result of Yeh [Yeh, C.-H., 2008. An efficiency characterization of plurality rule in collective choice...