(New) 7 July 2026, Computational Social Choice Seminar, Rachel Ruellé

Abstract

In social choice theory, we often need to analyze the internal structure of a profile of preferences reported by the members of a group. In this talk, we will discuss different approaches to measuring such structural properties of preference profiles, in particular diversity and polarization. Broadly speaking, we speak of polarization when we can split the group into two subgroups with conflicting preferences, while each subgroup enjoys a high level of internal cohesiveness. Diversity, on the other hand, refers to the complexity of a preference profile, tracking features such as the overall number of distinct preferences and the distance between any two of them. We will define several proposals for preference structure indices to measure such features and formulate a number of axioms those indices arguably should satisfy. This includes both concepts from the literature and new ones.

For more information on the Computational Social Choice Seminar, please consult https://staff.science.uva.nl/u.endriss/seminar/.