The Dynamic Pivot Mechanism
针对代理人随时间获得私人信息的环境，提出基于边际贡献的动态枢轴机制，满足事后激励与参与约束，并在重复拍卖中等价于修正的第二价格拍卖。
We consider truthful implementation of the socially e¢ cient allocation in an independent private-value environment in which agents receive private information over time. We propose a suitable generalization of the pivot mechanism, based on the marginal contribution of each agent. In the dynamic pivot mechanism, the ex-post incentive and ex-post participation constraints are satis…ed for all agents after all histories. In an environment with diverse preferences it is the unique mechanism satisfying ex-post incentive, ex-post participation and e¢ cient exit conditions. We develop the dynamic pivot mechanism in detail for a repeated auction of a single object in which each bidder learns over time her true valuation of the object. We show that the dynamic pivot mechanism is equivalent to a modi…ed second price auction.