Umberto Grandi: Measuring and Controlling Divisiveness in Rank Aggregation

Thursday January 26, 2023 at 10am. (room A707)

Umberto Grandi (Université Toulouse 1 Capitole)

Title: Measuring and Controlling Divisiveness in Rank Aggregation

Abstract:
In rank aggregation, members of a population rank issues to decide which are collectively preferred. We focus instead on identifying divisive issues that express disagreements among the preferences of individuals.  We analyse the properties of these divisiveness measures and their relation to existing notions of polarisation. We also study their robustness under incomplete preferences and algorithms for control and manipulation of divisiveness. Our results advance our understanding of how to quantify disagreements in collective decision-making. [joint work with Racahel Colley, Cesar Hidalgo, Mariana Macedo, and Carlos Navarrete from the University of Toulouse]