On number of limit cycles for the quadratic systems with a weak focus and a strong focus

Applied Mathematics

Volumn 16, Issue 2, 2001, Pages 127-132

  Zhang, Pingguang ^a   Zhao, Shenqi ^a  

^a ZHEJIANG UNIVERSITY   (China)

Author keywords

Number of limit cycle; Quadratic differential system; Strong focus; Weak focus

Indexed keywords

EID: 84979031564     PISSN: 10051031     EISSN: None     Source Type: Journal    
DOI: 10.1007/s11766-001-0018-y     Document Type: Article

References (7)

1. Zhang Pingguang, Cai Suilin, Quadratic systems with a weak focus, Bull. Math. Austral. Math. Soc., 1991,44:511-526.
2. Zhang Pingguang, Li Wenhua, A quadratic system with weak focus and strong focus, Ann. Differential Equations, 1992, 8(1):122-128.
3. Zhang Pingguang, Quadratic systems with a weak focus and a strong focus, Appl. Math. J. Chinese Univ. Set. B, 1999, 14:7-14.
4. Li Chengzhi, Non-existence LCs around a fine focus of order 3 of quadratic systems, Chinese Ann. Math. Ser. B, 1986, 7(2):174-190.
5. Zhang Pingguang, On the uniqueness of the limit cycle around a 2nd-order weak focus for quadratic systems, Acta Math. Sinica, 1999, 42(2):289-304.
6. Ye Yangqian, et al., Theory of Limit Cycle, Translation of Math. Monographs 66, American Math. Society, Providence, R.I., 1986.
7. Zhang Zhifen, et al., Qualitative Theory of Differential Equation, Modern Math. Basic Series, Science Press, Beijing, 1985.