Verifying Proportionality in Temporal Voting
This addresses a computational challenge for researchers and practitioners in voting systems, but it is incremental as it builds on prior work in multiwinner elections.
The paper tackles the problem of verifying proportional representation in temporal voting, showing that verification is strictly harder than in multiwinner voting but identifying efficient algorithms for natural special cases.
We study a model of temporal voting where there is a fixed time horizon, and at each round the voters report their preferences over the available candidates and a single candidate is selected. Prior work has adapted popular notions of justified representation as well as voting rules that provide strong representation guarantees from the multiwinner election setting to this model. In our work, we focus on the complexity of verifying whether a given outcome offers proportional representation. We show that in the temporal setting verification is strictly harder than in multiwinner voting, but identify natural special cases that enable efficient algorithms.