关于方程f″+Af=F(z)的复振荡

本文讨论了当A(z)为多项式,F(z)为具有无穷多个零点的整函数时,微分方程 f″+A(z)f=F(z)的解f(z)的复振荡的性质.     

亚纯系数的非齐次线性微分方程的振荡解

本文研究关于亚纯系数的非齐次线性微分方程的复振荡,得到方程f(k)+ak-1fk-1+…+a0f=F(a0,a1,…,ak-1和F是亚纯函数)具有一个振荡解空间,其空间中所有解的零点收敛指数为∞,至多除去一个例外值.     

微分方程f″ e~(az)f′ Q(z)f=F(z)的复振荡

该文研究了线性微分方程f″ eazf′ Q( z) f=F( z)的复振荡问题,其中Q( z)、F( z) ( 0 )是整函数,且σ( Q) =1 ,σ( F) < ∞,Q( z) =h( z) ebz,h( z)是多项式,b≠- 1是复常数,那么上述线性微分方程的所有解f( z)满足λ( f) =λ( f) =σ( f) =∞,　λ2 ( f) =λ2 ( f) =σ2 ( f) =1 .至多除去两个例外复数a及一个可能的有穷级例外解f0 ( z) .     

一类二阶微分方程的解和小函数的关系

在文中研究了一类二阶线性微分方程的解以及它们的一阶,二阶导数,微分多项式与小函数之间的关系．     

一类高阶线性微分方程解的复振荡

In this paper,we shall use Nevanlinna theory of meromorphic functions to investigate the complex oscillation theory of solutions of some higher order linear differential equation.Suppose that A is a transcendental entire function with ρ(A)<1/2.Suppose that k≥2 and f(k)+A(z)f=0 has a solution f with λ(f)<ρ(A),and suppose that A1=A+h,where h≡0 is an entire function with ρ(h)<ρ(A).Then g(k)+A1(z)g=0 does not have a solution g with λ(g)<∞.     

Entire solutions of differential equations with finite order transcendental entire coefficients

In this paper, we investigate the complex oscillation of the differential equation

高阶微分方程解的辐角分布

设A0,A1,c,An-1是不全为多项式的有限级整函数.本文研究微分方程f(n)+An-1f(n-1)+…+A0f=0解的辐角分布并得到解的零点可去集的一个结果.     

微分方程f″+e^{az}f′+Q(z)f=F(z) 的复振荡

该文研究了线性微分方程f″+e^{az}f′+Q(z)f=F(z)的复振荡问题,其中Q(z)、F(z )( 0)是整函数,且σ(Q)=1,σ(F)<+∞,Q(z)=h(z)e^{bz},h(z)是多项式,b≠-1是复常数,那么上述线性微分方程的所有解f(z)满足~λ(f)=λ(f)=σ(f)=∞,~λ_2(f)=λ_2(f)=σ_2(f)=1.至多除去两个例外复数a及一个可能的有穷级例外解f_0(z)。     

一类高阶线性微分方程解的增长性

本文研究了在Aj(z),aj(j=0,1,…,k-1)满足一些条件下方程f(k)+Ak-1(z)eak-1f(k-1)+…+A0(z)ea0zf=0解的超级和在Aj(z),Pj(j)(j=0,1,…,k-1)满足一些条件下方程f(k)+Ak-1(z)ePk-1(z)f(k-1)+…+Aj(z)eajzf(j)+…+A0(z)eP0(z)f=0解的级。     

A computational comparison of the first nine members of a determinantal family of root-finding methods

For each natural number m greater than one, and each natural number k less than or equal to m, there exists a root-finding iteration function, B_m^(k) defined as the ratio of two determinants that depend on the first m−k derivatives of the given function. This infinite family is derived in Kalantari (J. Comput. Appl. Math. 126 (2000) 287–318) and its order of convergence is analyzed in Kalantari (BIT 39 (1999) 96–109). In this paper we give a computational study of the first nine root-finding methods. These include Newton, secant, and Halley methods. Our computational results with polynomials of degree up to 30 reveal that for small degree polynomials B_m^(k−1) is more efficient than B_m^(k), but as the degree increases, B_m^(k) becomes more efficient than B_m^(k−1). The most efficient of the nine methods is B₄⁽⁴⁾, having theoretical order of convergence equal to 1.927. Newton's method which is often viewed as the method of choice is in fact the least efficient method.     

亚纯系数齐次线性微分方程解的性质

本文研究了慢增长亚纯系数齐次线性微分方程亚纯解的零点收敛指数,得到了这类方程的线性无关超越解的最少个数和零点收敛指数为有穷的解的最多个数。     

高阶线性微分方程解的二阶导数的不动点

研究了以整函数为系数的高阶线性微分方程解的二阶导数的不动点,得到的两个结果推广了一些相关结论.     

一类高阶齐次线性微分方程解的零点

本文研究一类整函数系数高阶齐次线性微分方程解的零点分布.利用Nevanlinna值分布理论,得到当系数A_(k-1)的增长性起主要支配作用时,方程f~((k))+A_(k-1)f~((k-1))+···+A_0f=0任意超越解的零点收敛指数为无穷,推广了Langley和Bank等人的结果.     

An entire function and its derivatives sharing a polynomial

In this paper, we study the growth of solutions of a first-order linear differential equation and that of a second-order linear differential equation. From this we obtain some uniqueness theorems of a nonconstant entire function and its first derivative having the same fixed points with the same multiplicities. The results in this paper also improve some known results. Some examples show that the results in this paper are best possible.     

On the uniqueness problems of entire functions and their derivatives

In this paper, we obtain some uniqueness theorems for entire functions and their derivatives sharing the same fixed points with the same multiplicities.     

PERTURBATIONS OF ZEROS OF SOLUTIONS TO SECOND ORDER DIFFERENTIAL EQUATIONS WITH POLYNOMIAL COEFFICIENTS＊

Let P(z) and (P)(z) be polynomials of the same degree. We consider the equations u\" =P(z)u and (u)\" =(P)(z)(u) (z ∈ C) whose solutions are u(z) and (u)(z),respectively.Let zk(u) and zk((u)),k =1,2,…,be...     

一阶时超微分方程解的零点分布

利用一类新的迫近数列,讨论了一阶时超微分方程解的零点分布.     

Fermat型复微分--差分方程的整函数解*

利用值分布理论,研究了一类Fermat型复微分-差分方程与复微分-差分方程组,得到有限级超越整函数解的存在条件与具体形式,推广改进了高凌云、刘凯、曾翠萍等人的结果.