This exercise generalizes Aumann's Agreement Theorem to a set of players of arbitrary finite size.
Given an Aumann model of incomplete information with beliefs (N, Y, (Fi)i∈N , s, P) with n players, suppose that for each i ∈ N, the fact that player i describes probability qi to an event A is common knowledge among the players. Prove that q1 = q2 =···= qn.