The Proportional Veto Principle for Approval Ballots

Halpern, Daniel; Procaccia, Ariel D.; Suksompong, Warut

doi:10.24963/ijcai.2025/434

The Proportional Veto Principle for Approval Ballots

Daniel Halpern, Ariel D. Procaccia, Warut Suksompong

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Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence. Main Track. Pages 3900-3907.

https://doi.org/10.24963/ijcai.2025/434

Keywords

Game Theory and Economic Paradigms: GTEP: Computational social choice

Abstract

The proportional veto principle, which captures the idea that a candidate vetoed by a large group of voters should not be chosen, has been studied for ranked ballots in single-winner voting. We introduce a version of this principle for approval ballots, which we call flexible-voter representation (FVR). We show that while the approval voting rule and other natural scoring rules provide the optimal FVR guarantee only for some flexibility threshold, there exists a scoring rule that is FVR-optimal for all thresholds simultaneously. We also extend our results to multi-winner voting.

Daniel Halpern, Ariel D. Procaccia, and Warut Suksompong. 2025. The Proportional Veto Principle for Approval Ballots. In Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence, IJCAI-25. IJCAI, 3900–3907. https://doi.org/10.24963/ijcai.2025/434

@inproceedings{ijcai2025p434,
  title     = {The Proportional Veto Principle for Approval Ballots},
  author    = {Halpern, Daniel and Procaccia, Ariel D. and Suksompong, Warut},
  booktitle = {Proceedings of the Thirty-Fourth International Joint Conference on
               Artificial Intelligence, {IJCAI-25}},
  publisher = {International Joint Conferences on Artificial Intelligence Organization},
  editor    = {James Kwok},
  pages     = {3900--3907},
  year      = {2025},
  month     = {8},
  note      = {Main Track},
  doi       = {10.24963/ijcai.2025/434},
  url       = {https://doi.org/10.24963/ijcai.2025/434},
}

TY  - CPAPER
TI  - The Proportional Veto Principle for Approval Ballots
AU  - Halpern, Daniel
AU  - Procaccia, Ariel D.
AU  - Suksompong, Warut
T2  - Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence, IJCAI-25
PB  - International Joint Conferences on Artificial Intelligence Organization
PY  - 2025
SP  - 3900
EP  - 3907
DO  - 10.24963/ijcai.2025/434
UR  - https://doi.org/10.24963/ijcai.2025/434
ER  -