{"type":"ScholarlyArticle","title":"The Proportional Veto Principle for Approval Ballots","authors":[{"name":"Daniel Halpern","slug":"daniel-halpern","given":"Daniel","family":"Halpern","affiliation":""},{"name":"Ariel D. Procaccia","slug":"ariel-d-procaccia","given":"Ariel D.","family":"Procaccia","affiliation":""},{"name":"Warut Suksompong","slug":"warut-suksompong","given":"Warut","family":"Suksompong","affiliation":""}],"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.","doi":"10.24963/ijcai.2025/434","url":"https://ijcai.org/proceedings/2025/434","pdf":"https://ijcai.org/proceedings/2025/0434.pdf","markdown":"https://ijcai.org/proceedings/2025/434.md","bibtex":"https://ijcai.org/proceedings/2025/bibtex/434","volume":{"slug":"2025","title":"Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 2025","url":"https://ijcai.org/proceedings/2025/","year":2025,"location":"Montreal, Canada","dates":"16-22 August 2025","editors":"James Kwok","isbn":"978-1-956792-06-5","publisher":"International Joint Conferences on Artificial Intelligence Organization","doi_prefix":"10.24963/ijcai.2025"},"section":"Game Theory and Economic Paradigms","track":"Main Track","number":434,"pages":{"first":3900,"last":3907},"keywords":["Game Theory and Economic Paradigms: GTEP: Computational social choice"],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}