摘要
本文给出结果：（１）一类具有不少于［3/8n^2］个一阶细焦点的平面ｎ次系统．（２）一类具有不少于［３/8n^2］族权限环的平面ｎ次系统．
In this paper, we give the following results: (1) A class of planar n-polynomial system with at least [n2] weak focus of order 1. (2) A class of planar n-polynomial system with at least [n2] family limit cycles.
出处
《数学学报（中文版）》
SCIE
CSCD
北大核心
2000年第2期245-252,共8页
Acta Mathematica Sinica：Chinese Series
