## Oscillation theorems for damped differential equations of even order with deviating arguments.(English)Zbl 0542.34057

In this paper the oscillatory behaviour of the even order differential equations with deviating arguments of the form $x^{(n)}+p(t)x^{(n- 1)}+q(t)f(x[g_ 1(t)],x[g_ 2(t)],...,x[g_ m(t)])=0$ is discussed. The oscillation criteria are given which improve similar criteria established by C. C. Yeh [Proc. Am. Math. Soc. 84, 397-402 (1982; Zbl 0498.34023)] for $$\ddot x+p(t)\dot x+q(t)f(x)=0.$$ The conditions and the results are rather too complicated for reproducing here.

### MSC:

 34K99 Functional-differential equations (including equations with delayed, advanced or state-dependent argument)

Zbl 0498.34023
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