## Oscillatory properties of third order neutral delay differential equations.(English)Zbl 1060.34036

Summary: The authors consider the third-order neutral delay differential equation $(a(t)(b(t)(y(t)+ py(t- \tau))')')'+ q(t) f(y(t- \sigma))= 0,\tag{$$*$$}$ with $$a(t)> 0$$, $$b(t)> 0$$, $$q(t)\geq 0$$, $$0\leq p< 1$$, $$\tau> 0$$, and $$\sigma> 0$$. Criteria for the oscillation of all solutions of $$(*)$$ are obtained. Examples illustrating the results are included.

### MSC:

 34K11 Oscillation theory of functional-differential equations