Jun Iritani

Vetoer and tie-making group theorems for indifference-transitive aggregation rules

A binary relation is indifference-transitive if its symmetric part satisfies the transitivity axiom. We investigated the properties of Arrovian aggregation rules that generate acyclic and indifference-transitive social preferences. We proved that there exists unique vetoer in the rule if the number of alternatives is greater than or equal to four. We provided a classification of decisive structures in aggregation rules where the number of alternatives is equal to three. Furthermore, we showed that the coexistence of a vetoer and a tie-making group, which generates social indifference, is inevitable if the rule satisfies the indifference unanimity. The relationship between the vetoer and the tie-making group, i.e., whether the vetoer belongs to the tie-making group or not, determines the power structure of the rule.

Designing the optimal public pension system

This paper uses a two-period overlapping generations model in order to provide a theoretical design for an optimal public pension system based on a partial equilibrium analysis. Household preferences only depend on two periods consumption and leisure and is homogeneous of degree m with respect to consumption in the working and retired periods. We present characteristic features of an optimal public pension system in this paper. First, differences in the population growth rate do not affect the relative level of the optimal net lifetime burden rate of each generation. Second, if m≠0 or m