Is Perfect Price Discrimination Really Efficient? An Analysis of Free Entry
分析完全价格歧视与自由进入下的产品差异化模型，发现固定企业数时价格歧视可激励社会最优产品选择，但自由进入会导致企业数量过多。
We analyze models of product differentiation with perfect price discrimination and free entry.With a fixed number of firms, and in the absence of coordination failures, perfect price discrimination provides incentives for firms to choose product characteristics in a socially optimal way.However, with free entry, the number of firms is always excessive.Our results apply to a large class of models of product differentiation.They also apply to models of common agency or lobbying with free entry and imply that one has excessive entry into the ranks of the principals.