Choosing Collectively Optimal Sets of Alternatives Based on the Condorcet Criterion

Abstract

In elections, an alternative is said to be a Condorcet winner if it is preferred to any other alternative by a majority of voters. While this is a very attractive solution concept, many elections do not have a Condorcet winner. In this paper, we propose a setvalued relaxation of this concept, which we call a Condorcet winning set: such sets consist of alternatives that collectively dominate any other alternative. We also consider a more general version of this concept, where instead of domination by a majority of voters we require domination by a given fraction theta of voters; we refer to this concept as theta-winning set. We explore social choice-theoretic and algorithmic aspects of these solution concepts, both theoretically and empirically.

Cite

Text

Elkind et al. "Choosing Collectively Optimal Sets of Alternatives Based on the Condorcet Criterion." International Joint Conference on Artificial Intelligence, 2011. doi:10.5591/978-1-57735-516-8/IJCAI11-042

Markdown

[Elkind et al. "Choosing Collectively Optimal Sets of Alternatives Based on the Condorcet Criterion." International Joint Conference on Artificial Intelligence, 2011.](https://mlanthology.org/ijcai/2011/elkind2011ijcai-choosing/) doi:10.5591/978-1-57735-516-8/IJCAI11-042

BibTeX

@inproceedings{elkind2011ijcai-choosing,
  title     = {{Choosing Collectively Optimal Sets of Alternatives Based on the Condorcet Criterion}},
  author    = {Elkind, Edith and Lang, Jérôme and Saffidine, Abdallah},
  booktitle = {International Joint Conference on Artificial Intelligence},
  year      = {2011},
  pages     = {186-191},
  doi       = {10.5591/978-1-57735-516-8/IJCAI11-042},
  url       = {https://mlanthology.org/ijcai/2011/elkind2011ijcai-choosing/}
}