Advances in Difference Equations
Volume 2010 (2010), Article ID 262461, 17 pages
Research Article

Existence of 2n Positive Periodic Solutions to n-Species Nonautonomous Food Chains with Harvesting Terms

1Department of Mathematics, Yunnan University, Kunming, Yunnan 650091, China
2Department of Mathematics, Yuxi Normal University, Yuxi, Yunnan 653100, China

Received 12 November 2009; Accepted 10 January 2010

Academic Editor: Gaston Mandata N'Guerekata

Copyright © 2010 Yongkun Li and Kaihong Zhao. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


By using Mawhin's continuation theorem of coincidence degree theory and some skills of inequalities, we establish the existence of at least 2n positive periodic solutions for n-species nonautonomous Lotka-Volterra type food chains with harvesting terms. An example is given to illustrate the effectiveness of our results.