Coordinating Monetary Contributions in Participatory Budgeting

Abstract

We formalize a framework for coordinating the funding of projects and sharing the costs among agents with quasi-linear utility functions and individual budgets. Our model contains the classical discrete participatory budgeting model as a special case, while capturing other well-motivated problems. We propose several important axioms and objectives and study how well they can be simultaneously satisfied.One of our main results is that whereas welfare maximization admits an FPTAS, welfare maximization subject to a well-motivated and very weak participation requirement leads to a strong inapproximability result. We show that this result is bypassed if we consider some natural restricted valuations or when we take an average-case heuristic approach.

The (Computational) Social Choice Take on Indivisible Participatory Budgeting

“…Finally, they investigate several welfare maximisation rules-based on utilitarian, egalitarian, or Nash social welfare-in terms of these axioms. Aziz, Gujar, Padala, Suzuki and Vollen (2022) study the same model except that agents submit cardinal ballots instead of approval ones. ey focus on the computational aspects of maximising the utilitarian social welfare subject to some participation requirements (that guarantees the agents not to contribute more than they receive), showing both computational hardness and inapproximability of the problem.…”

“…Jain, Sornat and Talmon (2020) looked into social welfare for non-additive satisfaction functions. Social welfare has been studied in multi-resources PB (Motamed, Soeteman, Rey and Endriss, 2022), when the cost is dependent on the number of users of the projects (Lu and Boutilier, 2011), and when the budget is endogenous (Aziz and Ganguly, 2021;Aziz, Gujar, Padala, Suzuki and Vollen, 2022;Chen, Lackner and Maly, 2022).…”