suppose antonio and trinity are playing a game that requires both to simultaneously choose an action: up or down. the payoff matrix that follows shows the earnings of each person as a function of both of their choices. for example, the upper-right cell shows that if antonio chooses up and trinity chooses down, antonio will receive a payoff of 4 and trinity will receive a payoff of 5. trinity up down antonio up 4, 8 4, 5 down 2, 2 3, 4