讲座：A Taxonomy of Unidimensional Non-dictatorial Domains
题 目：A Taxonomy of Unidimensional Non-dictatorial Domains
地 点：上海交通大学 徐汇校区安泰经济与管理学院A305室
A preference domain is called a non-dictatorial domain if it allows the design of unanimous social choice functions (henceforth, rules) that are non-dictatorial and strategy-proof; otherwise it is called a dictatorial domain. We study a class of preference domains called unidimensional domains and establish that within this class, the unique seconds property (introduced by Aswal, Chatterji and Sen (2003)) separates non-dictatorial domains from dictatorial domains. The principal contribution of the paper is the subsequent exhaustive classification of all non-dictatorial unidimensional domains based on a simple property of two-voter rules called invariance. The preference domains that constitute the classification are semi-single-peaked domains (introduced by Chatterji, Sanver and Sen (2013)) and semi-hybrid domains (introduced here) which are two appropriate weakenings of single-peaked domains and which, importantly, are shown to allow strategy-proof rules to depend on non-peak information of voters' preferences. As a refinement of the classification, single-peaked domains and hybrid domains emerge as the only unidimensional domains that force strategy-proof rules to be determined completely by the peaks of voters' preferences.
Huaxia Zeng graduated, as a Ph.D. in Economics, from Singapore Management University in 2016, and joined Shanghai University of Finance and Economics as a tenure-track associate professor in 2018. His research concentrates on mechanism design theory with special interests in voting, assignment and auction models. He has published several research papers on Games and Economic Behavior, Journal of Economic Theory, Journal of Mathematical Economics and Theoretical Economics.