Oscillation for nonlinear second order dynamic equations on a time scale

We obtain some oscillation criteria for solutions to the nonlinear dynamic equation xΔΔ +q(t)xΔσ + p(t)(f ◦ xσ ) = 0, on time scales. In particular, no explicit sign assumptions are made with respect to the coefficients p(t), q(t). We illustrate the results by several examples, including a superlinear Emden–Fowler dynamic equation.  2004 Elsevier Inc. All rights reserved.