Welfare Changes in the Cournot Setting with an Empirical Application to the Telecommunications Industry
研究了古诺均衡的效率，给出了企业数量变化时消费者剩余、生产者剩余和社会福利损失的界限，并应用于葡萄牙固话市场，发现2007年拆分垄断者后福利显著增加。
I characterize the efficiency of the Cournot equilibrium and provide bounds for the loss in consumer surplus, producer surplus and welfare when the number of firms in the market changes. I only assume that demand is decreasing in price and costs increasing in the quantity produced as long as equilibrium exists. I show how price, demand and average cost, before and after the number of firms in the market changes, can be used to compute these bounds. I apply these bounds to the Portuguese wireline market and conclude that welfare increased significantly when the monopolist was split in 2007.