感觉是一个数学高手修炼到很高的境界之后返璞归真

作者通过通俗的语言来一步步引入一些很复杂的概念，让人明白是怎么一步步来的。。。由其关于维度那一块的讲述，太赞了，简要记录如下：
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同一维度中，直线和曲线是完全等同的，没有差别，差别主要来自于他们嵌入的高维空间的方式不同, space they are embedded. The difference between two curves can be detected by two-dimensional creatures living in the plane.
What curved means is that one space has been stuck inside another in such a way that its intrinsic metric disagrees with that of the larger outside space.
如a constant motion on circle ---------- helix （螺旋线）
人类一生如果看做是在三维空间中的运动，那么在四维空间中观察的话就是一条静止的曲线。
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