Efficiently Computing Equilibria in Budget-Aggregation Games

Budgetaggregationdealswiththesocialchoiceproblemofdistributing an exogenously given budget among a set of public projects, given agents’ preferences. Taking a game-theoretic perspective, we study budget-aggregation games where each agent has virtual decision power over some fraction of the budget. We investigate the structure and show efficient computability of Nash equilibria for various common preference models in this setting. In particular, we show that equilibria for Leontief utilities can be found in polynomial time, solving an open problem from Brandt et al. [15], and give an explicit polynomial-time algorithm for computing equilibria for ℓ1 preferences.

Authors

• Patrick Becker TU Munich
• Alexander Fries TU Munich
• Matthias Greger Paris Dauphine - PSL
• Erel Segal-Halevi Ariel University

Keywords

• Budget aggregation
• Equilibrium computation
• Nash equilibrium