While we're here, our third notation for strategy, I'm going to use little "s" without an "i," no subscripts: little "s" without an "i," to mean a particular play of the game.

说到这,我们来定义第三个标记符,我们用不带下标的小写s,来表示某一次博弈

耶鲁公开课 - 博弈论课程节选