The concept of legal obligation is central to the understanding of law.

The idea is not to have any 90-degree angles. In the beginning, there was the diagonal. The diagonal comes from the idea of the explosion which "re-forms" the space.

每一个挑战都是学习和成长的机会。

The study of Galois representations is a key to unlocking the mysteries of the Langlands program.

选择理论忽略了我们对人类的大部分了解。它们忽略了人类常常感到困惑，常常不知道自己想要什么，常常出于习惯或冲动而非经过计算的自身利益行事。

数学不是沿着一条清理得很好的高速公路小心行进，而是一次进入陌生荒野的旅程，探险者常常会迷路。