拓扑绝缘体的美在于它们的鲁棒性；它们的表面态受到保护，不受无序和缺陷的影响。

The central task of education is to implant a will and facility for learning; it should produce not learned but learning people. The truly human society is a learning society, where grandparents, parents, and children are students together.

The concept of NP-completeness has provided a powerful tool for understanding the complexity of problems.