Prove the following claims for n-player extensive-form games:
(a) Adding information to one of the players does not increase the maxmin or the minmax value of the other players.
(b) Adding information to one of the players does not increase the minmax value of the other players.
(c) Adding information to one of the players may have no effect on his maxmin value.
(d) Adding information to one of the players may decrease the maxmin value of the other players.