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Oscillation theorems for linear differential equations of second order. (English) Zbl 0661.34030
Some new oscillation criteria are given for second order ordinary differential equations of the form ${x}^{\text{'}\text{'}}\left(t\right)+a\left(t\right)x\left(t\right)=0,$ $t\ge {t}_{0}$, where a is a continuous real-valued function on the interval $\left[{t}_{0},\infty \right)$ without any restriction on its sign. These criteria extend and improve previous oscillations results due to I. V. Kamenev [Mat. Zametki 23, 249-251 (1978; Zbl 0386.34032)] and J. Yan [Proc. Am. Math. Soc. 98, 276-282 (1986; Zbl 0622.34027)]. The results obtained can be applied in some cases in which other known oscillation theorems are not applicable.
Reviewer: Ch.G.Philos

##### MSC:
 34C10 Qualitative theory of oscillations of ODE: zeros, disconjugacy and comparison theory 34A30 Linear ODE and systems, general
##### References:
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