k-prize Weighted Voting Game

We introduce a natural variant of the weighted voting game, which we refer to as the k-Prize Weighted Voting Game. Such a game consists of 𝑛 players with weights, and 𝑘 prizes, of differing values. Players in the game form coalitions, and the 𝑖-th largest coalition (by the sum of weights of its members) then wins the 𝑖-th largest prize, which is shared among its members. We present four solution concepts for the game, and fully characterise the existence of stable outcomes in games with uniform prizes, and in games with 3 players and 2 prizes. We also explore the efficiency of stable outcomes, namely whether they are Pareto-optimal or maximise utilitarian social welfare, and study the complexity of finding stable outcomes in such games.