Electronic Journal of Differential Equations,
Vol. 2009(2009), No. 66, pp. 1-10.

Title: Multiple nonnegative solutions for second-order boundary-value
       problems with sign-changing nonlinearities
   
Authors: Shouliang Xi (Univ. of Shanghai for Science and Tech., China)
         Mei Jia      (Univ. of Shanghai for Science and Tech., China)
	 Huipeng Ji   (Univ. of Shanghai for Science and Tech., China)

Abstract:
 In this paper, we study the existence of multiple nonnegative
 solutions for second-order boundary-value problems of differential
 equations with sign-changing nonlinearities.
 Our main tools are the fixed-point theorem in double cones and
 the Leggett-Williams fixed point theorem. We present also the
 integral kernel associated with the boundary-value problem.

Submitted  December 8, 2008. Published May 14, 2009.
Math Subject Classifications: 34B10, 34B18.
Key Words: Nonnegative solutions; fixed-point theorem in double cones;
           integral kernel; integral boundary conditions.