for externalities, substitutabilities and complementarities. Firms' cost parameter is private information and is … independently distributed across firms. Externalities are type dependent. This has two consequences: first, even though the private …, which makes the use of variational methods possible. A further consequence of having type-dependent externalities, which …

, private information, and identity-dependent externalities. We derive the seller's optimal mechanism and characterize its main … commonly used in practice is an optimal mechanism if externalities are sufficiently large …