具有正负系数的二阶中立型方程的振动性定理

Oscillation theorems of second order neutral differential equations with positive and negative coefficients

利用Banach空间的不动点原理,通过引入参数函数和Riccati变换,获得了该类方程存在非振动解的新的准则,并同时得到了该类方程振动的判别准则,这些准则改善了对方程的条件限制,所得结论推广并改进了现有文献中的一系列结果.

Using the fixed point theorem in Banach space,and by introducing parameter function and the generalized Riccati transformation,a new nonoscillation criteria for the equation was obtained.In addition,a sufficient condition for oscillation of the equation was proposed.These criteria can improve the restriction of the conditions for the equation. Some existed results in the literatures have been further improved and extended.