We derive a necessary and a sufficient condition for Nash implementation with a procedurally fair mechanism. Our result has a nice analogue with the path-braking result of Maskin [Nash equilibrium and welfare optimality, Rev. Econ. Stud. 66 (1999) 23-38.], and therefore, it allows us to give a...

Recent developments in voting theory show that Condorcet profiles embedded in electoratesare responsible for conflicts between pairwise voting methods and for reversals ofrankings under positional methods whenever candidates are dropped or added. Because ofthe strong symmetry of the rankings of...

In this paper we provide two simple new versions of Arrow’s impossibility theorem, in a model with only one preference profile. Both versions are transparent, requiring minimal mathematical sophistication. The first version assumes there are only two people in society, whose preferences are...

We investigate the computational complexity of several decision problems in hedonic coalition formation games and demonstrate that attaining stability in such games remains NP-hard even when they are additive. Precisely, we prove that when either core stability or strict core stability is under...

A collective decision problem is described by a set of agents, a profile of single-peaked preferences over the real line and a number k of public facilities to be located. We consider public facilities that do not suffer from congestion and are non-excludable. We provide a characterization of...

A competitive rent-seeking club (CRSC) offers its members the chance of winning a prize (status, position, privilege) by being selected, typically, by a civil servant or a politician. The selector replaces in our setting the usual contest success function; instead of determining the winner on...

The characteristics of endogenously determined sharing rules and the group-size paradox are studied in a model of group contest with the following features: (i) The prize has mixed privatepublic good characteristics. (ii) Groups can differ in marginal cost of effort and their membership size....

Collective contests are examined permitting heterogeneity of stakes within every competing group. Our first concern is whether unequal distribution of stakes in a group can enhance its win probability. Our second concern is whether a large stake in a group can be individually disadvantageous. We...

This paper studies collective contests with endogenous cost sharing, general effort costs and intra-group heterogeneity of prize-valuation. Our objective is to clarify the relationship between cost sharing, intra-group heterogeneity within the competing groups and the elasticity of the marginal...

The form of contests for a single fixed prize can be determined by a designer who maximizes the contestants' efforts. This paper establishes that, under common knowledge of the two asymmetric contestants' prize valuations, a fair Tullock-type endogenously determined lottery is always superior to...