We consider a dynamic auction environment with a long-lived seller and short-lived buyers mediated by a third party. A mediator has incomplete information about traders' values and selects an auction mechanism to maximize her expected revenue. We characterize mediator-optimal mechanisms and show...

We show how to bid in first-price auctions when a bidder knows her own value but not how others will bid. To do this we introduce a novel and general method for how to make choices in strategic settings without assuming common knowledge or equilibrium behavior. Accordingly, first eliminate...