【关键词】解析向量场 环域 极限环 奇点 孤立的周期解 Analytic Vector Field Annular Region Limit Cycles Singular Points Isolated Periodic Solutions
【摘要】 Isolation in isolated periodic solutions implies that the system neither exists other periodic solu-tions nor exists singular points of the system in its neighborhood. We give examples to illustrate that the closed trajectories in an annular region a...
