具有4n^2+2n+1阶奇点的一类2n+1次系统

A Class of(2n+1)th System with one 4n^2+2n+1 Order Singularity

研究了一类具有两个零特征根和一个4n2+2n+1阶奇点的2n+1次系统,并给出了极限环存在与否的条件。

A class of （2n＋1）th system with one 4n^2＋2n＋1 order singular point and two zero eigenvalue is studied, and some conditions of existence or nonexistence of the limit cycle are given.