Advances in Difference Equations 
Volume 2005 (2005), Issue 2, Pages 205-214
doi:10.1155/ADE.2005.205

Construction of upper and lower solutions for singular discrete initial and boundary value problems via inequality theory

Haishen Lü1 and Donal O'Regan2

 1Department of Applied Mathematics, Hohai University, Nanjing 210098, China
2Department of Mathematics, National University of Ireland, Galway, Ireland
Received 25 May 2004

Abstract

We present new existence results for singular discrete initial and boundary value problems. In particular our nonlinearity may be singular in its dependent variable and is allowed to change sign.