证明三次系统x.=y-εy^3,y.=x(1-x^2)+(α-x^2)y,ε〉0,当0〈1-α〈〈1时,在区域|y|〈1/√ε内含单奇点的极限环的存在性与唯一性.根据Hopf分支定理,证明了当0〈1-α〈〈1时,存在含单奇点的极限环,再由唯一性定理证明了当0〈1-α〈〈1时,含单奇点的极限环的唯一性.
For cubic system x=y-εy^3,y=x(1-x^2)+(α-x^2)y,the existence and uniqueness of limit cycles is proved in |y|〈1/√ε,when 0〈1-α〈〈1 and wher ε〉0.According to Hopf bifuration theorem, the existence of limit cycles is proved, when 0 〈 1 -α 〈〈 1. And by the uniqueness theorem, the uniqueness of limit cycles is proved, when 0 〈 1 - α〈〈 1.