So here's the straight line, and this line is the expected payoff to Player I from choosing Down as it depends on the probability that the other person chooses Right, and then once again, we can write down the equation.

这就是第三条直线了,它表示参与人I选择下获得的收益,是另一个参与人,选右概率的一个函数,对于这一条直线,我们依然能够给出方程式

耶鲁公开课 - 博弈论课程节选