We consider auction environments in which bidders must incur a cost to learn their valuations and study the optimal selling mechanisms in such environments. These mechanisms specify for each period, as a function of the bids in previous periods, which new potential buyers should be asked to bid....

Firms compete with prices and qualities in markets where consumers have heterogeneous preferences and cost characteristics. Consumers demand two goods, which can be supplied jointly or separately by firms. We consider two strategy regimes for firms: uniform price-quality pairs, and screening...