Refer to the weighted voting system
and the Banzhaf definition of power. (The four players are P1, P2, P3 and P4.)
The winning coalitions are
◦ only the grand coalition.
◦ all coalitions with two or more players except for {P
3, P
4}.
◦ all coalitions with three or more players.
◦ all coalitions with three or more players except for {P
2, P
3, P
4}.
◦ none of these