Consider a game with two players, each of whom has two types. The types of player 1 are T1 = {a, b}. The types of player 2 are T2 = {c, d}. Suppose the beliefs of the types are p1(c|a) = p2(a|c) = 0.25 and p1(c|b) = p2(a|d) = 0.75. Is there a common prior? If yes, construct one; if no, prove why not.