I show that Swan's (1970) independence result requires a multiplicative interaction between durability and all other quality attributes. Because there is no compelling argument for a multiplicativity in quality, monopolists tend to distort durability, even with constant marginal costs....

Lecture on the first SFB/TR 15 meeting, Gummersbach, July, 18 - 20, 2004: We develop a general theoretical framework of trade on a platform on which buyers and sellers interact. The platform may be owned by a single large, or many small independent or vertically integrated intermediaries. We...

Increased competition tends to benefit all buyers with increasing product variety and decreasing prices. However, if local and external market channels compete for the same class of products, increased competition from the external market crowds out local variety. Under local monopoly, local...