Three designs of auctions with quality thresholds are considered. The quality threshold is not known with certainty by the bidders. In one scheme, quality plans submitted by potential bidders are evaluated first and price bids for only those plans that have been approved are invited. The second...

This paper considers the situation where two products are sold by the same seller, but to disjoint sets of potential buyers. Externalities may arise from each market outcome to the other. The paper examines the nature of the seller's optimal mechanism, and, for example in the case of positive...