摘要
本文在文献[1～2]的基础上分别得到文中方程(1)和方程(8)存在唯一极限环的充要条件,从而彻底解决了极限环存在和唯一性问题。
On basis of papers[ 1 ]and[2], we obtain the sufficient and necessary condition of limit cycle's existence and uniqueness in the equations( 1 )and( 8 ). Thuswe have thoronghly solved the problem about the existence and uniqueness of lim-it cycles. In addition, the method to judge the center and focus of equation( 8 ) is new.
基金
国家自然科学基金
关键词
生态系统
极限环
存在性
唯一性
ecological system, limit cycle, existence, uniqueness
