Multiwinner Temporal Voting with Aversion to Change
<|reference_start|>Multiwinner Temporal Voting with Aversion to Change: We study two-stage committee elections where voters have dynamic preferences over candidates; at each stage, a committee is chosen under a given voting rule. We are interested in identifying a winning committee for the second stage that overlaps as much as possible with the first-stage committee. We show a full complexity dichotomy for the class of Thiele rules: this problem is tractable for Approval Voting (AV) and hard for all other Thiele rules (including, in particular, Proportional Approval Voting and the Chamberlin-Courant rule). We extend this dichotomy to the greedy variants of Thiele rules. We also explore this problem from a parameterized complexity perspective for several natural parameters. We complement the theory with experimental analysis: e.g., we investigate the average number of changes in the committee as a function of changes in voters' preferences and the role of ties.<|reference_end|>
@article{zech2024multiwinner,
    title={Multiwinner Temporal Voting with Aversion to Change},
    author={Valentin Zech, Niclas Boehmer, Edith Elkind, Nicholas Teh},
    journal={arXiv preprint arXiv:2408.11017},
    year={2024},
    archivePrefix={arXiv},
    eprint={2408.11017},
    primaryClass={cs.GT cs.AI cs.CC}
}