We confront two common objections to Harsanyi's impartial observer theorem; one to do with 'fairness', and the other to do with different individuals' having different attitudes toward risk. Both these objections can be accommodated if we drop the reduction axiom; in particular, if we...

We consider the problem of allocating multiple units of an indivisible object among a set of agents and collecting payments. Each agent can receive multiple units of the object, and has a (possibly) non-quasi-linear preference on the set of (consumption) bundles. We assume that preferences...

We consider the election model in which voters choose a subset from the set of candidates. Both voters and candidates are assumed to possess preferences with separable strict orderings. We investigate a rule satisfying candidate stability, which is the requirement to deter any candidate from...

We consider the problem of allocating infinitely divisible commodities among a group of agents. Especially, we focus on the case where there are several commodities to be allocated, and agents have continuous, strictly convex, and separable preferences. In this paper, we establish that the...

We consider the problem of choosing a level of a public good on an interval of the real line among a group of agents. A probabilistic rule chooses a probability distribution over the interval for each preference profile. We investigate strategy-proof probabilistic rules in the case where...

This paper generalizes the results in Aswal et al. (2003) on dictatorial domains. This is done in two ways. In the first, the notion of connections between pairs of alternatives in Aswal et al. (2003) is weakened to weak connectedness. This notion requires the specification of four preference...

In this paper we consider the exogenous indifference classes model of Barberá and Ehlers (2011) and Sato (2009) and analyze further the relationship between the structure of indifference classes across agents and dictatorship results. The key to our approach is the pairwise partition graph. We...

Following Barberà, Sonnenschein, and Zhou (1991, Econometrica 59, 595-609), we study rules (or social choice functions) through which agents select a subset from a set of objects. We investigate domains on which there exist nontrivial strategy-proof rules. We establish that the set of separable...

We consider the problems of allocating several heterogeneous objects owned by governments to a group of agents and how much agents should pay. Each agent receives at most one object and has nonquasi-linear preferences. Nonquasi-linear preferences describe environments in which large-scale...

We study the problem of choosing prize winners from among a group of experts when each expert nominates another expert for the prize. A nomination rule determines the set of winners on the basis of the profile of nominations; the rule is impartial if one's nomination never influences one's own...