"The past is never dead. It's not even past."
Combinatorics is the art of counting without counting.
一个有纸、笔、橡皮擦并且坚持严格的行为准则的人,实质上就是一台通用图灵机。
翻译:事物的增减盈亏,都是随时间的变化而变化的。