Forced oscillation of higher order nonlinear difference equations

This paper considers the oscillation problem for forced nonlinear difference equations of the formΔmxn+qnf(xn-τ)=en.Δmxn+qnf(xn-τ)=en.We study three cases: qn ⩾ 0, qn < 0 and qn is oscillatory. No restriction assumed in known literatures is imposed on the forcing term en.