Advances in Difference Equations
Volume 2008 (2008), Article ID 695495, 12 pages
doi:10.1155/2008/695495

A generalized sum-difference inequality and applications to partial difference equations

Abstract

We establish a general form of sum-difference inequality in two variables, which includes both two distinct nonlinear sums without an assumption of monotonicity and a nonconstant term outside the sums. We employ a technique of monotonization and use a property of stronger monotonicity to give an estimate for the unknown function. Our result enables us to solve those discrete inequalities considered by Cheung and Ren (2006). Furthermore, we apply our result to a boundary value problem of a partial difference equation for boundedness, uniqueness, and continuous dependence.