摘要
设f(z)是开平面上的亚纯函数,N(r,f)为f(z)在圆|z|≤r上极点的计数函数,m(r,f)为逼近函数.T(r,f)=m(r,f)+N(r,f),T(r,f)称为f(z)的特征函数.F(z)=(fn)(z)+a1(z)f(n-1)(z)+…+an(z)f(z)是f(z)的线性微分多项式,其中n是正整数,a1(z),a2(z),…,an(z)均是f(z)的小函数.研究f(z)和F(z)的唯一性问题.证明了:f(z)为满足N(r,f)≤1f(z)的两个相互判别的小函数,若f(z)和F(x)几乎CM分担a(z)和b(z),则f(z)≡F(z).
Let f(z) be a meromorphic function in the whole complex plane; N( r, f) be the counting function of the poles on the disc: │z│≤r; m(r,f) be the proximity function. T(r,f) =m(r,f) +N(r,f) ,T(r,f) be characteristic function. F ( z ) =f^(n)( z ) + a1 ( z ) f^(n-1) ( z ) + … + an ( z ) f ( z ) be linear differential polynomial of f(z), where n is a positive integer and a1 (z) ,a2 (z) ,… ,an (z) are small functions related to f(z). The paper study the uniqueness question of f(z) and F (z). proves the following theorem: let./(z) be a nonconstant meromorphic function whith satisfying N(r,f)≤1/8n+17t(r,f) ; a(z) and b(z) two distinct small functions related tof(z). If f(z) and F(z) share a(z) and b(z) almost CM, then f(z) ≡F(z).
出处
《南京大学学报(自然科学版)》
CAS
CSCD
北大核心
2006年第1期17-21,共5页
Journal of Nanjing University(Natural Science)
基金
国家自然科学基金(10471065)
关键词
亚纯函数
分担函数
微分多项式
唯一性
meromorphic function, sharing function, differential polynomial, unicity