One can't proceed from the informal to the formal by formal means.
很大程度上運(yùn)氣是我有天才名譽(yù)的原因。在早上我不會(huì)走進(jìn)辦公室說“今天我聰明嗎？，而是說，“今天我幸運(yùn)嗎？——數(shù)學(xué)家相對(duì)于其他人來說最大的優(yōu)勢(shì)是，數(shù)學(xué)家深刻理解“概率。
The concept of polynomial-time reduction is central to understanding the structure of NP-complete problems.