我们不是从祖先那里继承了地球；我们是从子孙那里借来的——这必须指导每一个商业决策。

I have already carried out my duty. I have proved the Poincaré conjecture and I have nothing more to do in mathematics.

Mastery is not a function of genius or talent. It is a function of time and intense focus applied to a particular field of knowledge.

I'm not afraid to fail. I'm afraid of not trying.