Abstract This paper studies symmetry among countably infinitely many agents who randomly enter into a stochastic process, one for each period. Upon entry, they observe only the current period signal and try to draw inference about the underlying state governing the stochastic process. We show that there exist random entry models under which agents are ex post symmetric. That is, all agents have identical posterior belief about the underlying states, although they are not ex ante symmetric. The form of the posterior belief is uniquely pinned down by ex post symmetry and a stationarity condition. Our results provide a common prior foundation for the model studied in Liu and Skrzypacz (2014).

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关于事后对称随机进入模型的存在

摘要 本文研究了随机进入一个随机过程的可数无限多个代理之间的对称性，每个周期一个。进入时，他们只观察当前周期信号，并试图推断控制随机过程的潜在状态。我们表明存在随机进入模型，其中代理是事后对称的。也就是说，所有代理对潜在状态具有相同的后验信念，尽管它们不是事前对称的。后验信念的形式是由事后对称性和平稳性条件唯一确定的。我们的结果为 Liu 和 Skrzypacz (2014) 研究的模型提供了共同的先验基础。