TITLE: Trade-offs in Cost-sharing SPEAKER: Mukund Sundararajan Stanford University ABSTRACT: Auctions often involve multiple objectives in conflict. We focus on cost-sharing mechanisms for network design problems. Such auctions incur a cost dependent on the subset of players serviced. We would like such auctions to recover cost, be incentive compatible and maximize social efficiency (defined as the total value to the participants). Though it was well known that the three objectives cannot be achieved simultaneously, there was no meaningful way of quantifying the tension between the auction objectives. We propose a framework in which we express trade-offs between the auction objectives. The talk is based on joint work with Tim Roughgarden, Aranyak Mehta and Shuchi Chawla.