So what's the, shout it out, what's the profitable deviation here?

那这里存在什么样的有利变动呢
Profitable deviation is B.

策略B就是一种有利变动
It's not no because B is a strictly profitable deviation.

既然存在有利变动B它就不是纳什均衡
Notice that the thing that was a strictly profitable deviation

注意一下这里的有利变动
was the same thing that would have invaded the population of C's

和我们这一讲之前在讲进化时
in the context of our ant's nest and the context of this classroom

提到的蚁巢中入侵群体C
being an ant's nest and looking at evolution. Is that right?

是一样的道理是这样吧
So what have we just learned here?

从中我们能学到什么呢
Well this idea turns out to be general.

这个是一个很泛化的想法
The idea is if a strategy S,

这个想法就是说策略S
perhaps I should make this a lesson,

或许把它说成结论更好一些吧
if a strategy S is not Nash,

如果策略S不是纳什均衡