Efficiently Computing Equilibria in Budget-Aggregation Games
Published: Sep 10, 2025
Last Updated: Sep 11, 2025
Authors:Patrick Becker, Alexander Fries, Matthias Greger, Erel Segal-Halevi
Abstract
Budget aggregation deals with the social choice problem of distributing an exogenously given budget among a set of public projects, given agents' preferences. Taking a game-theoretic perspective, we initialize the study of budget-aggregation games where each agent has virtual decision power over some fraction of the budget. This paper investigates the structure and shows efficient computability of Nash equilibria in this setting for various preference models. In particular, we show that Nash equilibria for Leontief utilities can be found in polynomial time, solving an open problem from Brandt et al. [2023].