Existence of nonoscillatory solutions of higher-order neutral delay difference equations with variable coefficients

In this paper, we consider the following higher-order neutral delay difference equations with positive and negative coefficients: Δm(xn + cxn−k) + pnxn−r − qnxn−l = 0, n≥n0, where c ε R, m 1, k 1, r, l 0 are integers, and {pn}∞n=n0 and {qn}n=n0∞ are sequences of nonnegative real numbers. We obtain the global results (with respect to c) which are some sufficient conditions for the existences of nonoscillatory solutions.