Felix Brandt: Funding Public Goods: Collective Distribution of Individual Contributions III

A growing body of research at the intersection of mechanism design, social choice theory, and fair division studies how to allocate funds to public-interest projects based on the preferences of multiple agents. This tutorial focuses on settings where (i) projects are not associated with fixed costs and (ii) the budget to be distributed is supplied by the agents themselves. A natural application of this setting is donor coordination. Here, the agents are donors willing to contribute money for charitable giving, the public projects are charitable organizations, and the donors have preferences over how money should be distributed among charities. The tutorial will survey recent results in this area, discussing various types of utility functions, including linear, Cobb-Douglas, and Leontief utilities, and illuminate the pervasive conflict between efficiency, strategyproofness, and fairness. Highlights include the Nash product rule, the computer-aided proof of a sweeping impossibility, and natural spending dynamics that converge to socially desirable outcomes.