Discovering Consistent Subelections

We show how hidden interesting subelections can be discovered in ordinal elections. An interesting subelection consists of a reasonably large set of voters and a reasonably large set of candidates such that the former have a consistent opinion about the latter. Consistency may take various forms but we focus on three: Identity (all selected voters rank all selected candidates the same way), antagonism (half of the selected voters rank candidates in some order and the other half in the reverse order), and clones (all selected voters rank all selected candidates contiguously in the original election). We first study the computation of such hidden subelections. Second, we analyze synthetic and real-life data, and find that identifying hidden consistent subelections allows us to uncover some relevant concepts.

Authors

• Łukasz Janeczko AGH University of Science and Technology
• Jérôme Lang CNRS, Université Paris Dauphine, PSL
• Grzegorz Lisowski AGH University of Science and Technology
• Stanisław Szufa CNRS, LAMSADE, Université Paris Dauphine-PSL

Keywords

• Subelections
• Ordinal Elections
• Clones
• Computational Complexity