本文给出了拟二次系统的前18个奇点量和可积性条件,由此统一解决了几类实平面微分自治系统的初奇点、高次奇点以及无穷远点的中心焦点判定与极限环分枝问题.

In this paper, the first 18 values of singular point for quasi quadratic systems are obtained, for some kinds of real planar autonomous differential systems, the problems of determining center or focus and bifurcation of limit cysles for elementary critical point, higher critical point and infinite point are solved.