Abstract
Consider an extensive-form mechanism, run by an auctioneer who communicates sequentially and privately with agents. Suppose the auctioneer can deviate from the rules provided that no single agent detects the deviation. A mechanism is credible if it is incentive-compatible for the auctioneer to follow the rules. We study the optimal auctions in which only winners pay, under symmetric independent private values. The first-price auction is the unique credible static mechanism. The ascending auction is the unique credible strategy-proof mechanism. These results extend naturally when we permit asymmetry and payments from losing bidders.
https://drive.google.com/file/d/0B9jJAm-8bFh8R3h0SDREQnRUUUE/view