Necessary and Sufficient Conditions for the Oscillation of Forced Nonlinear Second Order Differential Equations with Delayed Argument

For a special class of the external force g t. and nonnegative potential a t., we give necessary and sufficient conditions for the oscillation of all solutions of a nonlinear second order forced differential equation with delayed argument of Emden]Fowler type in the form x0 t.qa t.< x f t..