Markov Perfect Industry Dynamics With Many Firms
提出一种近似方法分析Ericson和Pakes(1995)的不完全竞争动态模型，定义“遗忘均衡”概念，企业仅基于自身状态和长期平均行业状态决策，忽略竞争对手当前信息。遗忘均衡更易计算，且在大市场中能良好近似马尔可夫完美均衡。
We propose an approximation method for analyzing Ericson and Pakes (1995)-style dynamic models of imperfect competition. We define a new equilibrium concept that we call oblivious equilibrium, in which each firm is assumed to make decisions based only on its own state and knowledge of the long-run average industry state, but where firms ignore current information about competitors' states. The great advantage of oblivious equilibria is that they are much easier to compute than are Markov perfect equilibria. Moreover, we show that, as the market becomes large, if the equilibrium distribution of firm states obeys a certain "light-tail" condition, then oblivious equilibria closely approximate Markov perfect equilibria. This theorem justifies using oblivious equilibria to analyze Markov perfect industry dynamics in Ericson and Pakes (1995)-style models with many firms. Copyright 2008 The Econometric Society.