Characterizing the Plurality Rule via Clone Invariance

Abstract

The Plurality rule is vulnerable to vote splitting between similar alternatives. Defying conventional wisdom, we characterize the Plurality rule through a specific type of clone independence condition. We further introduce the notion of a one-parameter family of $p$-Clone Resistance ($p$-CR), and examine the property within the class of scoring rules. For $p\in (0,1)$, nontrivial rules exist with at most three alternatives, but only the Trivial rule generally satisfies the condition.