OSCILLATION FOR A CLASS OF LOGISTIC EQUATIONS

The oscillation of a delay difference equationis studied and the necessary and sufficient condition for all positive solutions of (E) to oscillate about its positive equilibrium is obtained.     

拟线性滞后型微分方程正解的存在性

本文研究了下面这种拟线性滞后型微分方程(g(u′)′+a(t) f (ut) =0 ,　　 0 1 ,满足非线性边界条件 .并且通过应用锥不动定理与阿尔采拉 -阿斯卡里定理 ,证明了上述方程至少存在一个正解 .     

偶数阶中立型泛函微分方程最终正解的存在性

获得了偶数阶中立型泛函微分方程[a(t)x(t)-b(t)x(t-r)](n) q(t)f(x(t-σ))=0 (t≥0)存在最终正解的充分条件．     

AN OSCILLATION CRITERION FOR EVEN ORDER NEUTRAL DIFFERENCE EQUATIONS

An oscillation criterion is obtained for even order neutral type differenceequations of the following formΔ~m(x_n+α_nx_(n-т))+f(n,x_n,x_(n-σ))=0,n=n_0,n_0+1,…,where m≥2 is even, n_0 is a nonnegative integer, Δ is the forward differenceoperator defined by Δx_n=x_(n+1)-x_n, and for i≥1, Δ~i is the i~(th)-order forwarddifference operator defined by Δ~ix_n=Δ(Δ~(i-1)x_n),т and σ are positive integers.