Abstract and Applied Analysis
Volume 2011 (2011), Article ID 310957, 15 pages
http://dx.doi.org/10.1155/2011/310957
Research Article

Existence and Multiplicity of Periodic Solutions Generated by Impulses

Liu Yang1,2 and Haibo Chen2

1Department of Mathematics and Computing Sciences, Hengyang Normal University, Hunan, Hengyang 421008, China
2Department of Mathematics, Central South University, Hunan, Changsha 421008, China

Received 30 October 2010; Accepted 23 March 2011

Academic Editor: Martin D. Schechter

Copyright © 2011 Liu Yang and Haibo Chen. 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.

Abstract

We investigate the existence and multiplicity of periodic solutions for a class of second-order differential systems with impulses. By using variational methods and critical point theory, we obtain such a system possesses at least one nonzero, two nonzero, or infinitely many periodic solutions generated by impulses under different conditions, respectively. Recent results in the literature are generalized and significantly improved.