Efficient and fair assignment mechanisms are strongly group manipulable

• 成果类型: Article
• 署名作者: Zhang, Jun
• 署名单位: Nanjing Audit University
• 刊物名称: JOURNAL OF ECONOMIC THEORY
• ISSN/ISSBN: 0022-0531
• DOI: 10.1016/j.jet.2018.12.005
• 发表日期: 2019
• 页码: 167-177
• 关键词: Random assignment; EFFICIENCY; fairness; Strong group manipulation

摘要

We study the assignment of indivisible objects to agents without using monetary transfers. We prove that, regardless of whether the number of objects is sufficient, a mechanism that satisfies ex-post Pareto efficiency, equal treatment of equals, equal total assignment (ETA), and uniform-head fairness (UHF) must be strongly manipulable by a group of agents. In other words, by misreporting their preferences, all group members can obtain lotteries that strictly first-order stochastically dominate the lotteries they would have obtained by reporting their true preferences. ETA requires that agents obtain equal total probability shares of objects. UHF requires that if all agents have equal preferences over a subset of objects and prefer the objects in that subset to the remaining objects, then they obtain equal probability shares of the objects in that subset. The random priority and probabilistic serial mechanisms satisfy our axioms. (C) 2018 Elsevier Inc. All rights reserved.