Preserving Consistency in Multi-Issue Liquid Democracy

Preserving Consistency in Multi-Issue Liquid Democracy

Rachael Colley, Umberto Grandi

Proceedings of the Thirty-First International Joint Conference on Artificial Intelligence
Main Track. Pages 201-207. https://doi.org/10.24963/ijcai.2022/29

Liquid democracy bridges the gap between direct and representative democracy by allowing agents to vote directly on an issue or delegate to a trusted voter. Yet, when applied to votes on multiple interconnected issues, liquid democracy can lead agents to submit inconsistent votes. Two approaches are possible to maintain consistency: either modify the voters' ballots by ignoring problematic delegations, or resolve all delegations and make changes to the final votes of the agents. We show that rules based on minimising such changes are NP-complete. We propose instead to elicit and apply the agents' priorities over the delegated issues, designing and analysing two algorithms that find consistent votes from the agents' delegations in polynomial time.
Keywords:
Agent-based and Multi-agent Systems: Computational Social Choice
Agent-based and Multi-agent Systems: Algorithmic Game Theory
Agent-based and Multi-agent Systems: Coordination and Cooperation