How do we know that everyone choosing 1 is the Nash Equilibrium in the game where you all chose numbers?

我们怎么知道在那个数字游戏中,选择1就是这个博弈的均衡呢

耶鲁公开课 - 博弈论课程节选

So in that game, what's the Nash Equilibrium in that game?

那个数字游戏中的纳什均衡是什么

耶鲁公开课 - 博弈论课程节选