yanqian造句

• In this dissertation , we study the global topological classification and coefficient conditions of the plane homogeneous fifth polynomial differential system the main techniques used in this thesis includes the methods of the global structure and coefficient conditions of the plane homogeneous quadratic and cubic system mentioned in the paper [ 1 ] of professor ye yanqian , and the paper [ 2 ] of professor li xue min , also includes the idea to high - order critical point of professor zhang zhifen , lu yulin and han yuliang etc . due to the degree of polynomial in the right of equal - sign crease , when we discuss the global structure , the more special directions , the more difficulty in drawing phase portraits of this system
  本文主要讨论一类平面齐五次多项式微分系统的全局拓扑结构及系数条件。借鉴了文献[ 1 ]叶彦谦教授对平面齐二次系统的全局结构及系数条件和文献[ 2 ]李学敏教授对平面齐三次系统的全局结构及系数条件的研究方法，同时综合了张芷芬教授、陆毓麟教授、韩玉良教授等人对高次奇点的研究思想进行讨论。这样，由于等号右边多项式次数的增加，讨论系统的全局结构时，可能出现的特殊方向就会增加，在作全局相图时，难度增大了。