The highest Player II ever chooses is 2, and the highest response that Player I ever makes to any strategy 2 or less is 6/4, so all these things bigger than 6/4 can go.

参与人II最大只会选策略2,参与人I针对这种情况下,最大只会选择6/4,即大于6/4的策略也会被剔除

耶鲁公开课 - 博弈论课程节选