不一致的达成

Agreeing to Disagree

如果1和2两个人都知道E事件,1知道2知道E事件,2知道1知道E事件,1知道2知道1知道E事件,以此类推,那么我们就称1和2对于E事件具有公共知识(common knowledge)。定理:如果两个人有相同的验前知识(prior),并且他们对于一个事件A的验后知识(posterior)是公共知识,那么,这些验后知识相等。

If both A and B know one event, A knows that B knows the event, or vice versa, we may conclude that both A and B have a common knowledge of this event. Here comes the law： If both persons have the common prior and their posterior is the common knowledge, then the posterior is equal.