The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.

即使追求效率，质量也绝不能妥协。

To write is to resist forgetting.

The time at our disposal each day is elastic; the passions we feel dilate it, those we inspire contract it; and habit fills up what remains.

解决一个数学问题就是揭开宇宙拼图的一块。