极限环存在的一个判定方法

An Equivalent Definition About Limit Cycle

文中利用中性流形概念．给出了极限环的一个等价定义，并依次得出了两个利用该定义判断极限环存在的相应定理与有关实例．

An equivalent definition alout limit cycle is given by the concept of neutral manifold in this article. According to that,two judgement theorems that limit cycles exist aregliven, and relevant liviny examples are given too.