Perhaps as important is the relation between the existence of solutions to a competitive equilibrium and the problems of normative or welfare economics.

The greatest glory in living lies not in never falling, but in rising every time we fall.

Memory is a form of creativity.

凡事有始有终。

摆脱诱惑的唯一方法就是屈服于它。

在数学中，你并不理解事物。你只是习惯了它们。

可持续林业不是成本，而是对韧性的投资。