An extension of May's Theorem to three alternatives: axiomatizing Minimax voting

Fuente: arXiv
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Main Authors: Holliday, Wesley H., Pacuit, Eric
Format: Preprint
Published: 2023
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author Holliday, Wesley H.
Pacuit, Eric
author_facet Holliday, Wesley H.
Pacuit, Eric
contents May's Theorem [K. O. May, Econometrica 20 (1952) 680-684] characterizes majority voting on two alternatives as the unique preferential voting method satisfying several simple axioms. Here we show that by adding some desirable axioms to May's axioms, we can uniquely determine how to vote on three alternatives (setting aside tiebreaking). In particular, we add two axioms stating that the voting method should mitigate spoiler effects and avoid the so-called strong no show paradox. We prove a theorem stating that any preferential voting method satisfying our enlarged set of axioms, which includes some weak homogeneity and preservation axioms, must choose from among the Minimax winners in all three-alternative elections. When applied to more than three alternatives, our axioms also distinguish Minimax from other known voting methods that coincide with or refine Minimax for three alternatives.
format Preprint
id arxiv_https___arxiv_org_abs_2312_14256
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle An extension of May's Theorem to three alternatives: axiomatizing Minimax voting
Holliday, Wesley H.
Pacuit, Eric
Theoretical Economics
Computer Science and Game Theory
Multiagent Systems
91B12, 91B14, 91B10
I.2.11
May's Theorem [K. O. May, Econometrica 20 (1952) 680-684] characterizes majority voting on two alternatives as the unique preferential voting method satisfying several simple axioms. Here we show that by adding some desirable axioms to May's axioms, we can uniquely determine how to vote on three alternatives (setting aside tiebreaking). In particular, we add two axioms stating that the voting method should mitigate spoiler effects and avoid the so-called strong no show paradox. We prove a theorem stating that any preferential voting method satisfying our enlarged set of axioms, which includes some weak homogeneity and preservation axioms, must choose from among the Minimax winners in all three-alternative elections. When applied to more than three alternatives, our axioms also distinguish Minimax from other known voting methods that coincide with or refine Minimax for three alternatives.
title An extension of May's Theorem to three alternatives: axiomatizing Minimax voting
topic Theoretical Economics
Computer Science and Game Theory
Multiagent Systems
91B12, 91B14, 91B10
I.2.11
url https://arxiv.org/abs/2312.14256