Stochastic Search Equilibrium
研究存在总体生产率冲击时，企业发布工资合同的搜索模型中的均衡工资与就业动态，证明了随机搜索均衡的存在性与唯一性，并发现该均衡下企业规模越大、生产率越高，提供的合同越优厚，且劳动力流动总是从低生产率企业流向高生产率企业。
We study equilibrium wage and employment dynamics in a class of popular search models with wage posting, in the presence of aggregate productivity shocks. Firms offer and commit to (Markov) contracts, which specify a wage contingent on all payoff-relevant states, but must pay equally all of their workers, who have limited commitment and are free to quit at any time. We find sufficient conditions for the existence and uniqueness of a stochastic search equilibrium in such contracts, which is Rank Preserving [RP]: larger and more productive firms offer more generous contracts to their workers in all states of the world. On the RP equilibrium path, turnover is always efficient as workers always move from less to more productive firms. The resulting stochastic dynamics of firm size provide an intuitive explanation for the empirical finding that large employers have more cyclical job creation (Moscarini and Postel-Vinay, 2012). Finally, computation of RP equilibrium contracts is tractable.