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 paper I prove that a quasiconcave separable utility defined on an atomless space is concave.

In this note I prove the existence of the optimal-pay auction when signals are correlated.

We discuss the issue, raised by Mas-Colell (1991) whether the local uniqueness (relative to the L∞ topology) may be a generic property of equilibria in incomplete markets economies with a continuum of states.