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Necessary and sufficient conditions for oscillations of higher order delay differential equations. (English) Zbl 0552.34063
Differential equations, Proc. Conf., Birmingham/Ala. 1983, North-Holland Math. Stud. 92, 373-379 (1984).
[For the entire collection see Zbl 0539.00010.]
We obtain necessary and sufficient conditions under which all solutions of certain nth order delay differential equations oscillate when n is odd, and necessary and sufficient conditions under which all bounded solutions oscillate when n is even. The conditions derived involve the characteristic equation of the delay differential equation.

34K99 Functional-differential equations (including equations with delayed, advanced or state-dependent argument)
34C10 Oscillation theory, zeros, disconjugacy and comparison theory for ordinary differential equations