Charity is typically carried out by individual donors, who donate money to charities they support, or by centralized organizations such as governments or municipalities, which collect individual contributions and distribute them among a set of charities. Individual charity respects the will of the donors, but may be inefficient due to a lack of coordination; centralized charity is potentially more efficient, but may ignore the will of individual donors. We present a mechanism that combines the advantages of both methods for donors with Leontief preferences (i.e., each donor seeks to maximize an individually weighted minimum of all contributions across the charities). The mechanism distributes the contribution of each donor efficiently such that no subset of donors has an incentive to redistribute their donations. Moreover, it is group-strategyproof, satisfies desirable monotonicity properties, maximizes Nash welfare, returns a unique Lindahl equilibrium, can be computed efficiently, and implemented via natural best-response spending dynamics.

翻译：慈善活动通常由个体捐赠者或中央组织（如政府或市政机构）实施。个体捐赠者将资金捐给自己支持的慈善机构，而中央组织则汇集个人捐款并分配给一组慈善机构。个体慈善尊重捐赠者的意愿，但可能因缺乏协调而效率低下；集中式慈善可能更高效，但可能忽视个体捐赠者的意愿。我们提出了一种机制，结合了两种方法的优势，适用于具有列昂季耶夫偏好（即每位捐赠者寻求最大化所有慈善机构捐款的个体加权最小值）的捐赠者。该机制高效分配每位捐赠者的捐款，使得任何捐赠者子集均无动机重新分配其捐款。此外，该机制具有群体策略防护性，满足理想的单调性特性，最大化纳什福利，返回唯一的林达尔均衡，可高效计算，并能通过自然的最佳响应支出动态实现。