Voting by sequential elimination with few voters

Voting by sequential elimination with few voters

Sylvain Bouveret, Yann Chevaleyre, François Durand, Jérôme Lang

Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence
Main track. Pages 128-134. https://doi.org/10.24963/ijcai.2017/19

We define a new class of low-communication voting rules, tailored for contexts with few voters and possibly many candidates. These rules are defined by a predefined sequence of voters: at each stage, the designated voter eliminates a candidate, and the last remaining candidate wins. We study both deterministic (non-anonymous) variants, and randomized (and anonymous) versions of these rules. We focus on a subfamily of these rules defined by ``non-interleaved'' sequences. We first focus on the axiomatic properties of our rules. Then we focus on the identification of the non-interleaved sequence that gives the best approximation of the Borda score under the impartial culture. Finally, we apply our rules to randomly generated data. Our conclusion is that, in contexts where there are more candidates than voters, elimination-based rules allow for a very low communication complexity (and especially, avoid asking voters to rank alternatives), and yet can be good approximations of common voting rules, while enjoying a number of good properties.
Keywords:
Agent-based and Multi-agent Systems: Agent Communication
Agent-based and Multi-agent Systems: Social Choice Theory