Market-Based Explanations of Collective Decisions


  • Dominik Peters Harvard University
  • Grzegorz Pierczyński University of Warsaw
  • Nisarg Shah University of Toronto
  • Piotr Skowron University of Warsaw



Social Choice / Voting


We consider approval-based committee elections, in which a size-k subset of available candidates must be selected given approval sets for each voter, indicating the candidates approved by the voter. A number of axioms capturing ideas of fairness and proportionality have been proposed for this framework. We argue that even the strongest of them, such as priceability and the core, only rule out certain undesirable committees, but fail to ensure that the selected committee is fair in all cases. We propose two new solution concepts, stable priceability and balanced stable priceability, and show that they select arguably fair committees. Our solution concepts come with a non-trivial-to-construct but easy-to-understand market-based explanation for why the chosen committee is fair. We show that stable priceability is closely related to the notion of Lindahl equilibrium from economics.




How to Cite

Peters, D., Pierczyński, G., Shah, N., & Skowron, P. (2021). Market-Based Explanations of Collective Decisions. Proceedings of the AAAI Conference on Artificial Intelligence, 35(6), 5656-5663.



AAAI Technical Track on Game Theory and Economic Paradigms