A Sufficient Condition for the Tops-Only Property of Strategy-Proof Social Choice Functions in the Case of Two Voters

Huaxia ZENG, Singapore Management University

Abstract

Read thesis at https://ink.library.smu.edu.sg/etd_coll/229.

In this thesis, we consider the standard voting model with a finite set of alternatives A and 2 voters, and address the following question: besides Domains D satisfying the

Property T (Chatterji & Sen (2011) ), what are other characteristics of domains that induce every strategy-proof and unanimous social choice function f : Dn A to satisfy the tops-only property? We impose a minimal richness condition which ensures that for every alternative a A, there exists a preference ordering where a is maximal. We identify a more general condition on domains that is sufficient for strategy-proofness and unanimity to imply tops-onlyness in the case of 2 voters. This condition is shown to apply to Linked Domains (Aswal, Chatterji & Sen (2003) ).