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Equitable Voting Rules
Author(s) -
Bartholdi Laurent,
HannCaruthers Wade,
Josyula Maya,
Tamuz Omer,
Yariv Leeat
Publication year - 2021
Publication title -
econometrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 16.7
H-Index - 199
eISSN - 1468-0262
pISSN - 0012-9682
DOI - 10.3982/ecta17032
Subject(s) - mathematical economics , voting , social choice theory , majority rule , equity (law) , foundation (evidence) , symmetry (geometry) , population , set (abstract data type) , fraction (chemistry) , group (periodic table) , mathematics , economics , econometrics , computer science , law , political science , sociology , artificial intelligence , physics , chemistry , geometry , demography , organic chemistry , politics , programming language , quantum mechanics
May's theorem (1952), a celebrated result in social choice, provides the foundation for majority rule. May's crucial assumption of symmetry, often thought of as a procedural equity requirement, is violated by many choice procedures that grant voters identical roles. We show that a weakening of May's symmetry assumption allows for a far richer set of rules that still treat voters equally. We show that such rules can have minimal winning coalitions comprising a vanishing fraction of the population, but not less than the square root of the population size. Methodologically, we introduce techniques from group theory and illustrate their usefulness for the analysis of social choice questions.