Competition and the Number of Firms in a Market: Are Duopolies More Competitive than Atomistic Markets?
用搜索模型变体分析市场均衡，发现边际搜索成本随搜索次数增加时，企业面临弯折需求曲线，价格对成本变化不敏感；企业数量增加时，最高价升至垄断价，最低价下降。
This paper uses a variant of the standard search model to examine market equilibrium and the consequences of an increase in the number of firms. If marginal search costs increase with the number of searches, then the demand curve facing any firm will be kinked, with the elasticity of demand with respect to price decreases being less than with respect to price increases; prices may not change in response to changes in marginal costs. As the number of firms increases, the maximum price that is consistent with equilibrium increases to the monopoly price, but the minimum price decreases. On the other hand, if marginal search costs decrease with the number of searches, equilibrium, if it exists, is characterized by a price distribution.