translation.en: They should have heard of it, but it's a little tricky to explain in technical detail, so I won't do it. I'll just mention it.  But Chen Ning Yang, called by us "Frank" Yang --  -- and Bob Mills put forward, 50 years ago, this generalization of Maxwell's equations, with a new symmetry.
translation.zh: 他们应当听说过它，但是把它解释清楚需要一些技巧， 所以我不准备这么做了。我就是稍微提一下。 杨振宁，我们叫他 夫兰克 杨 和罗伯特-米尔斯，在50年前提出的 这种对麦克斯韦方程组的概括有全新的对称性。