袁文俊. 关于二阶微分方程扰动理论一文的注记[J]. Journal of Xinjiang University (Natural Science Edition in Chinese and English), 1994, (2).DOI:
关于二阶微分方程扰动理论一文的注记
摘要
本文讨论微分方程y″+A(z)y=0解的复振荡,得到4个定理.推广了I.Laine[1]的两个定理
Abstract
In this paper we obtain the following theorenms:THEOREM l:Let A(z) be a finite-order σ>0 meromorphic function. Suppose that the second order linear diferential equation possesses two lineary independent solutions y1
y2 such that (1) P is a σ-degree polynomial;(2) Q1. Q2 are meromorphic functions of order less than σ andQ2=THEOREM 2: Let A(z) be a finite - order σ>0 meromorphic function. Let f1
f2 be two linearly independent solutions of (1)such that (2) holds. Then for any meromorphic function B (z) 0 of order σ(B)0. Let Q be a meromorphic function of T(r
Q ) = 0{t(r
eP)}. Suppose that the differential equation yn+(eP + Q )y= 0 possesses a non - trivial solution y such that max {λ(y) .λ(y1)} 0 entire function. Suppose that (1) possesses two linearly independent solutions y1