主题：美国求学执教的见闻和感受（0） -- changshou

if we go with 克莱因几何学埃尔朗根纲领 and define 时空 in terms of 变换群群论

伽利略变换群=伽利略时空, where classical physics=law of physics;

the problem with 伽利略变换群, not working with 麦克斯韦方程, from there on, 爱因斯坦狭义相对论.

爱因斯坦狭义相对论洛伦兹事件变换群=闵科夫斯基时空 where 狭义相对论=is the ruling law of physics;

in above 2 时空, 几何 is largely 歐幾里德几何/測度, and for that, we don't need to have 微分几何;

GR, 规范变换群=GR时空, 洛伦兹流形, "but" law of physics=几何, "back" to 柏拉圖 methodology?