© The London Mathematical Society
Periodic Solutions of Second Order Self-Adjoint Difference Equations
School of Science, Guangzhou University Guangzhou 5100405, China, jsyu{at}gzhu.edu.cn, gzm100{at}21cn.com
Department of Applied Mathematics, University of Western Ontario London, Ontario, Canada N6A 5B7, xzou{at}uwo.ca
Received 12 August 2003. Revision received 10 March 2004.
Using critical point theory, some sufficient conditions are obtained for the existence of nonconstant T-periodic solutions of a class of second order self-adjoint difference equations.