Profit is important, but it should never come at the expense of our principles.

The only way to make money is to not lose it.

The only way to deal with an unfree world is to become so absolutely free that your very existence is an act of rebellion.

数学研究是所有智力和精神进步不可或缺的基础。

【译文】 孔子说：“有益的朋友有三种，有害的朋友有三种。与正直的人交朋友、与诚实的人交朋友、与见多识广的人交朋友，有益处；与走邪门歪道的人交朋友、与谗媚奉迎的人交朋友、与花言巧语的人交朋友，有害处。”