2022/08/26 by Ernesto Savaglio, Savaglio, Ernesto, Stefano Vannucci +1
Computer Science · Decision Sciences · Economics, Econometrics and Finance · #Advanced Algebra and Logic #FOS: Economics and business #Game Theory and Voting Systems #Multi-Criteria Decision Making #Theoretical Economics (econ.TH)
paper · pdf · doi:10.48550/arxiv.2208.12732
openalex publication_date 2022/08/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Two characterizations of the whole class of strategy-proof aggregation rules on rich domains of locally unimodal preorders in finite median join-semilattices are provided. In particular, it is shown that such a class consists precisely of generalized weak sponsorship rules induced by certain families of order filters of the coalition poset. It follows that the co-majority rule and many other inclusive aggregation rules belong to that class. The co-majority rule for an odd number of agents is characterized and shown to be equivalent to a Condorcet-Kemeny median rule. Applications to preference aggregation rules including Arrowian social welfare functions are also considered. The existence of strategy-proof anonymous, weakly neutral and unanimity-respecting social welfare functions which are defined on arbitrary profiles of total preorders and satisfy a suitably relaxed independence condition is shown to follow from our characterizations.