Diego Canales

A model of k-winners

Abstract: The concept of Condorcet-winner (CW) has become central to most electoral models in the Political Economy literature. In its most simple terms, a CW is defined as the alternative that is preferred by a majority in every pairwise competition. If we consider a sequential electoral setting where candidates decide to quit (either sequentially or simultaneously) at any stage, such as the presidential primaries in the United States, a particular concept will arise: k−winners. This idea generalises the concept of a CW. The k−winner is the alternative that is top-ranked by the majority in every competition composed exactly of k candidates. We present a full characterisation of this theoretical result, using a game-theoretical model where a continuum of citizens vote, according to their ranked preferences, from a sequence of candidates in a sequential series of primaries.  More specifically, we find sufficient and necessary conditions for the existence of the of the k−winner for any k > 2.

Lunch from 12.30pm