该文讨论的是一类多项式系统:dx/dt=-y+δx+lx2+mxy+ax3,dy/dt=x(1+b1y+b2y2+…+bnxn)(bn≠0),求出该系统在O(0,0)的焦点量公式,得出在δma=0时系统至多存在一个极限环的结论.
In this paper, a class of polynomical systems:dx/dt=-y+δx+lx2+mxy+ax3,dy/dt=x(1+b1y+b2y2+…+bnxn)is studied. It gives the succesive focal values, and provesthat the system has at most one limit cycle when δma = O.