Collective decisions are modeled by preference correspondences (rules). In particular, we focus on a new condition: “update monotonicity” for preference rules. Although many so-called impossibility theorems for the choice rules are based on–or related to–monotonicity conditions, this...

Impossibility theorems for preference correspondences based on a new monotonicity concept are discussed. Here monotonicity means that if preferences update in such a way that they get closer to an outcome then at the new situation this outcome remains chosen. Strong monotonicity requires further...

In this paper, we study the measurement of polarization in collective decision making problems with ordinal preferences over alternatives. We argue that polarization can be measured as an aggregation of antagonisms over pairs of alternatives in the society. We propose a measure of this sort and...

This paper constructs a normative framework to quantify the difference (distance) between outcomes of market mechanisms in matching markets. We investigate the "cost of transformation" from one market mechanism to another, based on the differences in the outputs of these mechanisms, i.e., the...