Robust equilibria in tournaments

• 成果类型: Article
• 署名作者: Han, Lining; Juarez, Ruben; Vargas, Miguel
• 署名单位: Wuhan University; University of Hawaii System; University of Hawaii System
• 刊物名称: GAMES AND ECONOMIC BEHAVIOR
• ISSN/ISSBN: 0899-8256
• DOI: 10.1016/j.geb.2023.08.012
• 发表日期: 2023
• 页码: 423-439
• 关键词: Coalition formation; Robust equilibria; tournament; externalities

摘要

We study robust equilibria in tournaments, where agents endowed with power form coalitions, and the coalition formed with the highest power prevails. We introduce the No-Threat Equilibrium (NTE), a stable partition where if a coalition deviates, then a new coalition could counter by forming an even stronger coalition. The NTE exists for any power function and preferences if and only if the set of feasible coalitions is a 'Helly' family. In contrast, the core is a partition in which no group of agents can profitably deviate by forming a feasible coalition, assuming that other agents do not react to such a deviation. The core is not empty for any power function and preferences if and only if the set of feasible coalitions has a 'hierarchical-structure'. The paper also adapts and characterizes other stability concepts to tournaments, including the alpha-core, beta-core, farsighted core and bargaining set.(c) 2023 Elsevier Inc. All rights reserved.