On Coalitional Manipulation for Multiwinner Elections: Shortlisting
Abstract
Shortlisting of candidates--selecting a group of "best" candidates--is a special case of multiwinner elections. We provide the first in-depth study of the computational complexity of strategic voting for shortlisting based on the perhaps most basic voting rule in this scenario, l-Bloc (every voter approves l candidates). In particular, we investigate the influence of several tie-breaking mechanisms (e.g., pessimistic versus optimistic) and group evaluation functions (e.g., egalitarian versus utilitarian). Among other things, conclude that in an egalitarian setting strategic voting may indeed be computationally intractable regardless of the tie-breaking rule. Altogether, we provide a fairly comprehensive picture of the computational complexity landscape so far in the literature of this neglected scenario.
Cite
@article{arxiv.1806.10460,
title = {On Coalitional Manipulation for Multiwinner Elections: Shortlisting},
author = {Robert Bredereck and Andrzej Kaczmarczyk and Rolf Niedermeier},
journal= {arXiv preprint arXiv:1806.10460},
year = {2019}
}
Comments
An extended abstract of this work appeared in Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence (IJCAI-17), pp. 887-893, 2017