摘要
讨论厂三次Kolmogorov系统(?)=x(a_0+a_1x-a_2x^2-a_3y-a_4y^2),(?)=y(x^2-1)极限环的存在性和唯一性。
We consider the Kolmogorov differential system (?)=x(a_0+a_1x-a_2x^2-a_3y-a_4y^2), y=y(x^2-1), the conditions for the existence and uniqueness of limit cycle around positive cquilibrium point are obtained.
