Research Article
Existence of Positive Solutions of Nonlinear Second-Order Periodic Boundary Value Problems
Department of Mathematics, Northwest Normal University, Lanzhou 730070, China
Boundary Value Problems 2010, 2010:626054 doi:10.1155/2010/626054
Published: 25 November 2010Abstract
This paper is devoted to study the existence of periodic solutions of the second-order
equation 
, where 
is a Carathéodory function, by combining a new expression of Green's function together
with Dancer's global bifurcation theorem. Our main results are sharp and improve the
main results by Torres (2003).
