So here we have a second definition,

这里我们给出第二个定义
a new definition for today,

也是今天的一个新定义
and again we can use our jargon.

我们再一次用到术语
Definition-

定义是
Player i's strategy,

参与者i的策略s'i
"s'i" is weakly dominated by her strategy "si" if--

弱优于其他策略si当且仅当
now we're going to take advantage of our notation--

下面我们会发现用符号的好处了
if Player i's payoff

在对手选s-i的情况下下
from choosing "si" against "s-i"

参与人i选择si的收益
is always as big as or equal,

等于
to her payoff from choosing "s'i" against "s-i"

对手选s-i下她选s'i的收益
and this has to be true for all things that anyone else could do.

而且在任何情况下此条件均成立