The Condorcet set: Majority voting over interconnected propositions

• 成果类型: Article
• 署名作者: Nehring, Klaus; Pivato, Marcus; Puppe, Clemens
• 署名单位: University of California System; University of California Davis; Trent University; Helmholtz Association; Karlsruhe Institute of Technology
• 刊物名称: JOURNAL OF ECONOMIC THEORY
• ISSN/ISSBN: 0022-0531
• DOI: 10.1016/j.jet.2013.12.013
• 发表日期: 2014
• 页码: 268-303
• 关键词: Judgement aggregation; social choice; Condorcet set; Sequential majority voting; Path-dependence; indeterminacy

摘要

Judgement aggregation is a model of social choice in which the space of social alternatives is the set of consistent evaluations ('views') on a family of logically interconnected propositions, or yes/no issues. However, simply complying with the majority opinion in each issue often yields a logically inconsistent collective view. Thus, we consider the Condorcet set: the set of logically consistent views which agree with the majority on a maximal subset of issues. The elements of this set turn out to be exactly those that can be obtained through sequential majority voting, according to which issues are sequentially decided by simple majority unless earlier choices logically force the opposite decision. We investigate the size and structure of the Condorcet set for several important classes of judgement aggregation problems. While the Condorcet set verifies a version of McKelvey's (1979) celebrated 'chaos theorem' in a number of contexts, in others it is shown to be very regular and well-behaved. (C) 2014 Elsevier Inc. All rights reserved.