数学的本质不是使简单的事情复杂化，而是使复杂的事情简单化。

简单是终极的复杂。

My mission in life is not merely to survive, but to thrive; and to do so with some passion, some compassion, some humor, and some style.

As Will Rogers would have said, "There is no such thing as a free variable."

For the past 33 years， I have looked in the mirror every morning and asked myself: 'If today were the last day of my life， would I want to do what I am about to do today？' And whenever the answer has been 'No' for too many days in a row， I know I need to change something.