Some properties for certain classes of univalent functions defined by differential inequalities

Let A be the space of functions analytic in the unit disk D = {z:|z| 1}.Let U denote the set of all functions f ∈ A satisfying the conditions f(0) = f'(0)-1 = 0 and|f'(z)(z/f(z))~2-1|1(|z|1).Also,let Ω denote the set of all functions f ∈ A satisfying the conditions f(0) = f'(0)-1 = 0and|zf'(z)-f(z)|1/2(|z|1).In this article,we discuss the properties of U and Ω.     

关于有界平均振动亚纯函数

在[1]中我们曾引进有界平均振动亚纯函数的概念.设f(z)为D;|z|<1上的亚纯函数.记f(z)的球面导数为f~#(z)=|f'(z)|/(1 |f(z)|~2),又记f(z)=f((z )/(1 z)) ( <1).若满足条件称f(z)为具有有界平均振动的亚纯函数.这种函数的全体记作BMOM. 再引进 BMOM的一个子族.设f(z)为D上的亚纯函数,若满足条件     

Area Estimates of Images of Disks under Analytic Functions

Let D_r := {z = x + iy ∈ C : |z| r}, r ≤ 1. For a normalized analytic function f in the unit disk D := D1, estimating the Dirichlet integral Δ(r, f) =∫∫_(D_r)|f'(z)|~2 dxdy, z = x + iy, is an important classical problem in complex analysis. Geometrically, Δ(r, f) represents the area of the image of D_r under f counting multiplicities. In this paper, our main ob jective is to estimate areas of images of D_r under non-vanishing analytic functions of the form(z/f)~μ, μ 0, in principal powers,when f ranges over certain classes of analytic and univalent functions in D.     

关于单位圆内解析系数的二阶线性微分方程的复振荡

对二阶线性微分方程f" A1(z)f' A0(z)f=F(z)的复振荡进行了研究,其中系数Ai(z)(i=0,1)和F(z)是单位圆Δ={z|z|＜1}内的解析函数,获得解的超级和超零点收敛指数的估计,也得到了一些关于解的不动点的结果.     

The generalized Roper-Suffridge extension operator on bounded complete Reinhardt domains

The generalized Roper-Suffridge extension operator Ф(f) on the bounded complete Reinhardt domain Ω in Cn with n ≥ 2 is defined by Φrn,β2,γ2,…,βn,γn(f)(z)=(rf(z1/r),(rf(z1/r)/z1)β2(f'(z1/r))γ2z2,…,(rf(z1/r)/z1)βn(f'(z1/r)γnzn) for (z1,z2,…,zn) ∈Ω, where r = r(Ω) = sup{|z1| (z1,z2,…,zn) ∈ Ω},0 ≤ γj ≤ 1 -βj,0 ≤ βj ≤ 1,and we choose the branch of the power functions such that (f(z1)/z1)βj |z1=0 = 1 and (f′(z1))γj |z1=0 =1,j = 2,…,n. In this paper, we prove that the operator Фrn,β2,γ2,…,βn,γn(f) is from the subset of S*α(U) to S*α(Ω)(0 ≤ α ＜ 1) on Ω and the operator Фrn,β2,γ2,…, βn,γn(f) preserves the starlikeness of order α or the spirallikeness of type β on Dp for some suitable constantsβj,γj,pj, where Dp ={(z1,z2,…,zn) ∈ Cn ∑nj=1|zj|pj ＜ 1} (pj ＞ 0, j = 1,2,…,n), U is the unit disc in the complex plane C, and Sα* (Ω) is the class of all normalized starlike mappings of order α on Ω. We also obtain that Φrn,β2,γ2,…,γn(f) ∈ S*α(Dp) if and only if f ∈ S*a(U) for 0 ≤ α ＜ 1 and some suitable constants βj,γj,pj.     

关于单叶函数的两个定理

设f(x)=z+∑a_vx~v在圆|z|<1内单叶、正则,记这种函数的全体为S。对于S中的f(z),健根斯证得此处0相似文献   

A Remark on the Generalized Roper-Suffridge Extension Operator for Spirallike Mappings of Type β and Order α

Suppose f is a spirallike function of type β and order α on the unit disk D.let Ωn,p1,p2,…,pn={z=(z1,z2,…,zn)'∈Cn:nΣj=1|zj|pj<1},where 1≤p1≤2,pj≥1,j=2,…,n,are real numbers. In this paper,we will prove that Фn,β2,у2…βn,уn(f)(z)=(f(z1),(f(z1)z1)β2(f'(z1))у2z2,…,(f(z1)z1)βn(f'(z1))уnzn)' Preserves spirallikeness of type β and order α on Ωn,p1,p2,…pn.     

关于α次的殆星映射推广的Roper-Suffridge算子的一个注记

Suppose f is an almost starlike function of order α on the unit disk D. In this paper, we will prove that Φn, β2, γ2, …, βn, γn (f)(z) = (f(z1), (f(z1)/z1)β2(f'(z1))γ2z2,…,(f(z1)/z1)βn(f'(z11))γnzn)' preserves almost starlikeness of order α on Ωn,p1,p2,…,pn = {z =(z1,z2,…,zn)' ∈ Cn n∑j=1 |zj|pj ＜ 1}, where 0 ＜ p11 ≤ 2, pj ≥ 1, j = 2,…,n, are real numbers.     

论Szeg的定理(英文)

设f(z)=Z+a_2z~2+…∈S.Szeg证明:S_n(z)=z+a_2z~2+…+a_nz~n(n=2,3…)在|z|<1/4内单叶。ρ_O=1/4最好的,我们证明了更强的结果: 定理:若f(z)∈s.则s_n(z)(n=2,3…)在|z|<1/4内关于原点成星形。 当f∈S时为吴卓人所得。     

关于ROBINSON定理的改进

假设 f(z)和 F(z)是在单位圆盘中全纯的.假定(ZF(Z))′是单叶的,且(zf(z))′是从属于在单位圆盘中的(ZF(Z))′.Robinson 于1947年提出以下问题:如何决定 r,f(z)在|z|0.305….     

加权Dirichlet空间上的一般Cesàro算子

对加权Dirichlet空间我们研究了其上一般Cesaro算子的有界性．此处H(D)表示复平面单位圆盘D上全纯函数的全体．     

加权Dirichlet 空间上的一般Ces$\grave{a}$ro算子

对加权Dirichlet空间${\cal D}_{\alpha}=\left\{f\in H(D) ; ||f||_{{\cal D}_{\alpha}}^{2}=|f(0)|^{2}+\int_{D}|f'(z)|^{2}(1-|z|)^{\alpha}\d m(z)<+\infty \right\},~~-1<\alpha<+\infty,$我们研究了其上一般Ces$\grave{a}$ro算子的有界性. 此处$H(D)$表示复平面单位圆盘$D$上全纯函数的全体.     

Estimates of Conformal Radius and Distortion Theorems for Univalent Functions

A simple proof of the recent result by E. G. Emel'yanov concerning the maximum of the conformal radius r(D,1) for a family of simply connected domains with a fixed value r(D,0) is given. A similar problem is solved for a family of convex domains. Exact estimates for functionals of the form are obtained for families of functions inverse to elements of the classes S and S_m, where S={f:f is regular and univalent in the disk {z:|z| < 1} and f(0)=f'(0)-1=0} and S_M= for . Bibliography: 7 titles.     

典型實照函數的最小?妥钚∑

<正> 1.如果函數f(z)在包含實軸土某一區間的區域B中是正則的,f(z)在此實軸區間上取實值.在區域B的其餘地方f(z)與(z)同符號;即     

Bloch型函数的高阶径向导数

讨论了复超球上全纯函数的高阶导数的增长速度 ,证明了f∈Bα 的充分必要条件是supa∈B(1- ｜z｜2 ) m+α- 1｜Rmf(z) ｜ <∞ ,或supa∈B∫B(1-｜z｜2 ) (m+α- 1) ｜Rmf(z) ｜pJRφα(z)dv(z) <∞ ,或 (1- ｜z｜2 ) p(m+α- 1) ｜Rmf(z) ｜pdv(z)是Bergman Carleson测度 .     

Convex Holes Produce Lower Bounds for Coefficients

Let D denote the open unit disk and $ f:D \to \bar {{\bf C}}$ be meromorphic and injective in D . Especially, we consider such f which have an expansion $$ f(z) = z + \sum \limits_{n=2}^{\infty }a_n(\;f\,)z^n $$ in a neighbourhood of the origin and map D onto a domain whose complement with respect to $\bar {{\bf C}}$ is convex. Let the set of these functions be denoted by Co . We fix | f m 1 ( X )| for f ] Co and determine the inner and outer radius of the ring domain which is the domain of variability of a 2 ( f ) for such f . Further, it is shown that f ] Co implies that $$ \phi (z) = z+2 {f'(z) \over f''(z)}$$ is holomorphic in D and maps D into itself. This implication in turn implies the inequalities | a n ( f )| S 1 for f ] Co and n = 2,3,4. In addition, we show that | a n ( f )| S 1/2 for f ] Co and all n S 2 .     

P-Bloch函数的偏差定理和单叶半径

In this paper, we establish distortion theorems for both normalized p-Bloch functions with branch points and normalized locally univalent p-Bloch functions defined on the unit disk, respectively. These distortion theorems give lower bounds on |f′(z)| and ■f′(z). As applications of these distortion theorems, the lower bounds of the radius of the largest schlicht disk on these Bloch functions are given, respectively. Notice that when p = 1, our results reduce to that of Liu and Minda.     

α -正规函数的一些积分准则

对 0<α <∞, N^α 是开单位圆盘 D 上满足 sup _{z∈ D}(1-|z|²)^α f^# (z)<∞ 的亚纯函数类, 其中 f^# (z)=|f'(z)|/(1+|f(z)|²) 是 f 的球面导数. 该文给出了 D 上的 α -正规函数类的一些积分准则, 并用 Bergman-Carleson 测度的形式予以表示.     

Partial sums and the radius problem for some class of conformal mappings

Let $|\frac{{s_n (z)}} {{f(z)}} - 1| $|\frac{{s_n (z)}} {{f(z)}} - 1| when f ∈ $\left| {f'(z)\left( {\frac{z} {{f(z)}}} \right)^2 - 1} \right| < 1$\left| {f'(z)\left( {\frac{z} {{f(z)}}} \right)^2 - 1} \right| < 1     

复平面上解析Banach空间的拟不变子空间

讨论复平面上解析Banach空间具有任意指标的拟不变子空间的存在性问题.首先给出一类复平面上解析Banach空间存在任意指标拟不变子空间的判定定理.作为应用,证明了Fock型空间F~p(C)={f∈Hol(C):1/π∫_C|f(z)|~pe~(-|z|~2)dA(z)+∞,1≤p+∞}与Hilbert空间H={f∈Hol(C):1/π∫_C|f(z)|~2e~(-|z|)dA(z)+∞}具有任意指标的拟不变子空间.