逻辑是所有数学推理的基础。

The Milky Way’s black hole is our closest laboratory for studying extreme gravity.

When you are young spend at least 6 months to one year living as poor as you can， owning as little as you possibly can， eating beans and rice in a tiny room or tent， to experience what your “worst” lifestyle might be. That way any time you have to risk something in the future you won’t be afraid of the worst case scenario.

证明是一种可重复的说服实验。