In this paper, we study an auction where bidders only know the number of potential applicants. After seeing their values for the object, bidders decide whether or not to enter the auction. Players may not want to enter the auction since they have to pay participation costs. We characterize the...

In this note I show that pratically any increasing function is the equilibrium bidding function of a symmetric first-price auction. It is like a Sonnenschein-Mantel-Debreu for auctions