These strategies aren't dominated, nor are they dominated once you delete the dominated strategies, nor once we dominated the strategies dominated once we've deleted the dominated strategies, but they are dominated once we delete the strategies that have been dominated in the-- you get what I'm doing here.

选择20到30的策略一开始不处于劣势,在第一次剔除劣势策略时也不处于劣势,在第二次剔除势策略之后,也不处于劣势,但是在第三次剔除劣势策略之后,就变成劣势策略了,我想你们明白我的意思了

耶鲁公开课 - 博弈论课程节选

You can add something else to the answer without invalidating it, and that is anything with one power of t in it, because if you take one derivative it'll survive, but if you take two derivatives, it'll get wiped out.

你可以往答案后面加上其它东西,而且不影响结果,也就是任何t的一次项,因为你求一次导数之后它还在,但如果你求两次导数,这一项就不存在了

耶鲁公开课 - 基础物理课程节选