The essence of mathematics lies in its freedom.

The idea of inflation is that the universe underwent a period of extremely rapid expansion in its earliest moments.

I'm not a role model, but if it makes you sleep better at night, call me what you want.

译文：学习贵在实践，而非空知;贵在有用于世，而非无用之学。反对空谈，提倡经世致用。