Journal of Applied Mathematics
Volume 2011 (2011), Article ID 829107, 15 pages
Research Article

The Existence of Multiple Periodic Solutions of Nonautonomous Delay Differential Equations

College of Mathematics and Information Sciences, Guangzhou University, Guangzhou 510006, China

Received 13 March 2011; Accepted 13 May 2011

Academic Editor: Meng Fan

Copyright © 2011 Huafeng Xiao and Bo Zheng. 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.


We study the multiplicity of periodic solutions of nonautonomous delay differential equations which are asymptotically linear both at zero and at infinity. By making use of a theorem of Benci, some sufficient conditions are obtained to guarantee the existence of multiple periodic solutions.