Third‐Degree Price Discrimination in Oligopoly when Markets are Covered*
分析了市场全覆盖时寡头企业实行三级价格歧视与统一定价的均衡，发现统一定价能降低平均价格、提高消费者剩余，且仅需歧视均衡的市场数据即可计算福利变化。
We analyze oligopolistic third‐degree price discrimination relative to uniform pricing when markets are covered. Pricing equilibria are critically determined by supply‐side features such as the number of firms and their marginal cost differences. It follows that each firm's Lerner index under uniform pricing is equal to the weighted harmonic mean of the firm's relative margins under discriminatory pricing. Uniform pricing then lowers average prices and raises consumer surplus. We can calculate the gain in consumer surplus and loss in firms' profits from uniform pricing based only on the market data of the discriminatory equilibrium (i.e., prices and quantities).