5 December 2025, Computational Social Choice Seminar, Federico Fioravanti

Abstract

We consider the aggregation problem where a collective decision is based on binary evaluations of several issues. An expert is an agent who is decisive over an issue, and an aggregator is Pareto if it respects unanimous valuations over an issue. We study the required conditions for a domain to admit Pareto aggregators with at least two experts. We show that several impossibility results from the literature can be derived from our model, while establishing new results for settings such as the single-peaked domain and approval-based committee voting.