【直播】【QuACT系列报告】伏虎：The Vickrey Auction as a Prior Independent...

Bulow and Klemperer's theorem is a fundamental result in auction theory.  It states that, in a single-item auction where the n bidders' values are independently and identically drawn from a regular distribution, the Vickrey auction with one additional bidder (a duplicate) extracts at least as much revenue as the optimal auction without the duplicate. As a consequence of Bulow-Klemperer, the Vickrey auction is an approximately optimal auction for all regular distributions when there are at least two bidders.  We show that, interestingly, it is not the optimal such prior-independent auction, and survey recent works that yield further results in this direction. In the second half of the talk we show that, when the bidders' values are not necessarily drawn from an identical distribution, adding a carefully chosen duplicate suffices to help the Vickrey auction keep a constant fraction of the optimal revenue.  This improves the number of duplicates needed for such an approximation given in a well-known work by Hartline and Roughgarden (2009).