对上下极限的一些讨论

Some Discussions of the Upper and Lower Limits

摘要: 上下极限对于解决问题有着非常重要的作用，不管是在求解极限问题，还是在判断级数收敛以及实变函数中的定理，都运用着上下极限的概念，因此弄清楚上下极限之间关系，对处理问题起着关键作用。

Abstract: The upper and lower limits play an important role in solving the problem. Whether it is solving the limit problem or the theorem of the series convergence and the real variable function, the concept of the upper and lower limits is used. Therefore, to understand the relationship between the upper and lower limits plays a key role in dealing with the problem.