In this paper, we consider a natural procedure of decision-making, called a “Grouping Choice Method”, which leads to a kind of bounded rational choices. In this procedure a decision-maker (DM) first divides the set of available alternatives　into some groups and in each group she chooses...

In two-sided matching problems, we consider “natural” changes in preferences of agents in which only the rankings of current partners are enhanced. We introduce two desirable properties of matching rules under such rankenhancements of partners. One property requires that an agent who becomes...

Economic systems generate various distributions of opportunity sets for individuals to choose consumption bundles. This paper presents an axiomatic analysis on distributions of opportunity sets. We introduce several reasonable properties of distributions of opportunity sets, and characterize the...

Arrow's celebrated theorem shows that the aggregation of individuals' preferences into a social ordering cannot make the ranking of any pair of alternatives depend only on individuals' preferences over that pair, unless the fundamental Pareto and non-dictatorship principles are violated. In a...

Using an extended framework in which an agent is endowed with three types of preference orders: an allocation preference order, an opportunity preference order, and an overall preference order, this paper introduces several notions related to efficiency and equity-as-no-envy and examines the...

Arrow's celebrated theorem of social choice shows that the aggregation of individual preferences into a social ordering cannot make the ranking of any pair of alternatives depend only on individual preferences over that pair, unless the fundamental weak Pareto and nondictatorship principles are...

In a standard framework of choice theory, we formulate two contrasting principles for social choice under the efficiency-equity trade-off. The equity-first principle states that we should select from equitable allocations if any, but if the equity criterion is not at all effective for selection...

The theory of fair allocation is often favourably contrasted with the social choice theory in the search for escape routes from Arrow's impossibility theorem. Its success is commonly attributed to the fact that it is modest in its goal vis-`a-vis social choice theory, since it does not aspire...

In two-sided matching problems, we formulate (i) a concept of equity of matchings based on envy minimization, and (ii) a solidarity property of matching rules under "natural" and "simple" changes of preferences which represent enhancement of partnership of the pairs. We show that there exists no...

The Pareto efficiency criterion is often in conflict with the equity criteria as no-envy or as egalitarian-equivalence: An allocation x that is Pareto superior to another allocation y can be inferior to y in consideration of equity. This paper formalizes two differnet principles of social choice...