含多个奇点的Liénard方程极限环的唯二性问题

ON THE EXISTENCE OF AT MOST 2 LIMIT CYCLES SURROUDING MULTIPLE SINGULAR POINTS FOR LI NARD EQUATION

改进了微分方程定性理论中计算发散量积分的几个有用的引理,由之得到包围多个奇点的Liénard方程极限环的唯二性定理。

Some useful results in estimate the integral of divergence are improved,it follows that some sufficient conditions for Liénard equation are obtained which guarantees the existence of at most 2 limit cycles surrouding multiple singlar points.