Project Submission Games in Participatory Budgeting

TL;DR

This paper introduces project submission games to model proposer behavior in participatory budgeting, analyzing equilibrium existence, computational complexity, and algorithms for best responses.

Contribution

It formalizes a new game-theoretic framework for participatory budgeting, exploring equilibrium conditions and computational aspects.

Findings

Pure Nash equilibria existence conditions identified

Complexity results for equilibrium verification established

Algorithms for computing proposers' best responses developed

Abstract

We introduce the framework of project submission games, capturing the behavior of project proposers in participatory budgeting (and multiwinner elections). Here, each proposer submits a subset of project proposals, aiming at maximizing the total cost of those that get funded. We focus on finding conditions under which pure Nash equilibria (NE) exist in our games, and on the complexity of checking whether they exist. We also seek algorithms for computing best responses for the proposers