证明了对于一般的Ⅲ类二次系统。当O为一阶细焦点并且O外hopf分支产生的极限环与过鞍点N的同宿环相反时。在最优的条件下证明了极限环的大范围惟一性,从而改进了相关结论.
It is proved in this article: for general qudratic system of type Ⅲ, if N is an antisaddle and the finite critical points form a convex quadrangle, then there is only a limit cycle around O under the condition m 〈 0,l 〉1/2.