Oscillation of second-order nonlinear delay dynamic equations on time scales

In this paper, first, we establish the equivalence of the oscillation of the nonlinear dynamic equations x(Delta Delta) (t) + p(t)f(x(t -r)) = 0 and x(Delta Delta) (t) + p(t)(f o x(sigma)) = 0, on time scales, from which we obtain some oscillation criteria and comparison theorems for the first equation. Next, we obtain some new oscillation criteria for second-order linear dynamic equations on time scales. (c) 2005 Elsevier Ltd. All rights reserved.