关于可数复数集比较的一个引理的证明

Proof of a lemma on comparing two countable complex sets

通过构造辅助函数对比较可数复数集的一个引理给出详细的初等证明,从证明中可以很好地体会遍历理论的思想.该方法也可用于有限集的比较,因此讨论了有限情形的实质,并且给出该引理的一个应用.

The author gives a detailed elementary proof of a lemma on comparing two countable complex sets, from which one can grasp the idea of ergodic theory. This method can also be applied to the finite sets, in which case the essential ideas are discussed. An application of the lemma is also given.