BULLETIN OF THE KOREAN MATHEMATICAL SOCIETY, cilt.47, sa.2, ss.401-409, 2010 (SCI-Expanded)
In this paper, we introduce an iterative method to study oscillatory properties of delay difference equations of the following form del(alpha) [x (t) - r (t)x (t - kappa)] + p(t)x(t - tau) - q(t) x (t - sigma) = 0, t >= t(0), where t(0) is an element of R, t varies in the real interval [t(0), infinity), alpha > 0, kappa, tau, sigma >= 0, r is an element of C ([t(0) - alpha, infinity),R(+)), p,q is an element of C ([t(0), infinity), R(+)) and del x (t) = x (t) - x(t - alpha) for t >= t(0).