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...

In a market with indivisibilities, Roth and Postlewaite (1977) show that the (weak) core can suffer from instability problems, in the sense that groups of individuals might upset the equilibrium by recontracting among themselves. By contrast, the strong core is stable. Following the seminal...

We study the fair allocation of a one-dimensional and perfectly divisible good when individuals have other-regarding preferences. Assuming no legitimate claims and purely ordinal preferences, how should society measure social welfare so as to satisfy basic principles of efficiency and fairness?...

We analyze bankruptcy problems with an indivisible object, where real owners and outside traders want to allocate an indivisible object among them with monetary compensation. The object might be a company that has gone bankrupt or a house left by a parent who has died, and so on. We show that...

This paper studies coalitional strategy-proofness of social choice correspondences that map preference profiles into sets of alternatives. In particular, we focus on the Pareto rule, which associates the set of Pareto optimal alternatives with each preference profile, and examine whether or not...

This paper studies the possibility of secure implementation (Saijo, T., T. Sjöström, and T. Yamato (2007) "Secure Implementation," Theoretical Economics 2, pp. 203-229) in divisible and non-excludable public good economies with quasi-linear utility functions. Although Saijo, Sjöström, and...

A new class of preference-aggregation rules is proposed, weak-veto rules. Weak-veto rules are applicable in settings characterized by strong pre-existing views on the desirability of different outcomes, whose recommendations should be modified only in the presence of strenuous opposition. They...

We study strategy-proof rules for choosing between two alternatives. We consider the full preference domain which allows for indifference. In this framework, for strategy-proof rules, ontoness does not imply efficiency. We weaken the requirement of efficiency to ontoness and characterizes the...

This paper extends Harsanyi's Impartial Observer Theorem by introducing Knightian Uncertainty in the form of individual belief systems. It features an axiomatic framework of societal decision-making in the presence of individual uncertainty. The model allows the analysis of scenarios where...

Multidimensional welfare analysis has recently been revived by money-metric measures based on explicit fairness principles and the respect of individual preferences. To operationalize this approach, preference heterogeneity can be inferred from the observation of individual choices (revealed...