本文引入并研究了叶层结构的定向性，作为应用，讨论了李群在流形上的自由作用，给出了存在李群自由作用的一个必要条件。

In this paper, the orientability of foliations was investigated, and an application to the free action of Lie groups on manifolds was given as well.

youdao

他们认为，它应该用来保护个人权利和公共自由，在个人的努力无效时，它具有特殊的作用。

They believed that it should be used to protect individual rights and public liberty, and that it had a special role where individual effort was ineffective.

youdao

只有当船体从升降架上自由悬挂，脱离海床和周围泥浆的吸力作用时，打捞工作才进入第二阶段。

It was only when the hull was hanging freely from the lifting frame, clear of the seabed and the suction effect of the surrounding mud, that the salvage operation progressed to the second stage.

youdao

The government has liberized the economy and that has of course been playing a role but the growth acceleration started almost a decade before that, so the factors are a little more complex.

印度政府让经济自由发展,这一决策显然是起了作用的,但在这一决策出现约10年前,印度经济的加速发展便开始了,所以经济腾飞的原因还比较复杂。

普林斯顿公开课 - 国际座谈会课程节选

Conversely, if you get an answer and it doesn't seem to make sense, then you've got to go back and ask, am I violating some of the assumptions, and here you will find the assumption that the particle had that acceleration a is true as long it's freely falling under gravity but not when you hit the ground.

反过来说,如果你得到一个结果,发现似乎是错的,那么你就应该回过头来问问自己,我是不是违反某些前提了,这个模型中,你就发现,只要质点在重力作用下自由下落,质点具有加速度a的前提是正确的,但是落地后就不成立了

耶鲁公开课 - 基础物理课程节选