由卷积和从属关系刻画的单叶调和函数某些子类

Let SH be the class of functions f = h + ˉg that are harmonic univalent and sensepreserving in the open unit disk U = {z ∈ C : |z| 1} for which f(0) = f′(0)-1 = 0. In the present paper, we introduce some new subclasses of SH consisting of univalent and sensepreserving functions defined by convolution and subordination. Sufficient coefficient conditions,distortion bounds, extreme points and convolution properties for functions of these classes are obtained. Also, we discuss the radii of starlikeness and convexity.     

Third Hankel Determinant for the Inverse of Starlike and Convex Functions

Denote S to be the class of functions which are analytic, normalized and univalent in the open unit disk U = {z : |z| 1}. The important subclasses of S are the class of starlike and convex functions, which we denote by S~* and C.In this paper, we obtain the third Hankel determinant for the inverse of functions ■ elonging to S~* and C.     

Some radius problems related to a certain subclass of analytic functions

For real parameters α and β such that 0≤α1β,we denote by S(α,β) the class of normalized analytic functions which satisfy the following two-sided inequality:αR(zf′(z)/f(z))β,z∈U,where U denotes the open unit disk.We find a sufficient condition for functions to be in the class S(α,β) and solve several radius problems related to other well-known function classes.     

The Starlikeness of Analytic Functions of Koebe Type with Complex Order

For α 0, λ 0 and β,η∈R, we consider the M(α,λ)_b of normalized analyticα—λ convex functions defined in the open unit disc U. In this paper we investigate the class M(α, λ,β,η)_b,with f_b := z/(1-z~n)~b being Koebe type. By making use of Jack's Lemma as well as several differential and other inequalities, the authors derive sufficient conditions for starlikeness of the class M(α, λ, β, η)_b of n-fold symmetric analytic functions of Koebe type. Relevant connections of the results presented here with those given in earlier works are also indicated.     

Solutions of Equations Involving Analytic Functions in a Banach Algebra

By the properties of univalent analytic functions,we have discussed the exi-stence and uniqueness of eqation f(x)=a in a Banach algebra.We have the follo-wing fundamental lemmas. Lemma 1. Let A be a Banach algebra with identity e,W,U be two opensubsets of C, U W,f be an analytic function in W, and univalent in U, V=f(U),a∈A.If σ(a) V,then there exists unique x∈A such that σ(x) U {λ∈W|f(λ) V}and f(x)=a     

On pointwise bounded approximation

Let G be an open subset in the extended complex plane and let A（G） denote the algebra of all functions analytic on G and continuous on G. We call a domain multi-nicely connected if there is a circular domain W and a conformal map ~ from W onto G such that the boundary value function of φ is univalent almost everywhere with respect to the arclength on aW. Suppose that every component of G is finitely connected and none of the components of G have single point boundary components. We show that for every bounded analytic function on G to be the pointwise limit of a bounded sequence of functions in A（G）, it is necessary and sufficient that each component of G is multi-nicely connected and the harmonic measures of G are mutually singular. This generalizes the corresponding result of Davie for the case when the components of G are simply connected.     

Shannon-type sampling for multivariate non-bandlimited signals

In this paper, starting from a function analytic in a neighborhood of the unit disk and based on Bessel functions, we construct a family of generalized multivariate sinc functions, which are radial and named radial Bessel-sinc (RBS) functions being time-frequency atoms with nonlinear phase. We obtain a recursive formula for the RBS functions in R d with d being odd. Based on the RBS function, a corresponding sampling theorem for a class of non-bandlimited signals is established. We investigate a class of radial functions and prove that each of these functions can be extended to become a monogenic function between two parallel planes, where the monogencity is taken to be of the Clifford analysis sense.     

Some Univalence Conditions for a General Integral Operator

The authors consider the classes of the univalent functions denoted by SH(β),SP and SP(α,β).On these classes,the univalence conditions for a general integral operator are studied.     

Ma jorization Results and Coefficients Bounds for a Class of Univalent Functions Asso ciated with Operator

In this paper we introduce a new general subclass n,g ∑ a,λ(A, B,α) of univalent func-tions related the known integral operator and differential operator. Some majorization re-sults for n,g ∑ a,λ(A, B, 1) as well as the other functions are given. Furthermore, we find the coefficients bounds on|a2|and|a3|for functions in?n,g ∑ a,λ(A1, B1, A2, B2,α1,α2), which is the bi-univalent functions defined by n,g ∑ a,λ(A, B,α) and subordination. By giving specific values of the parameters of our main results, several(known or new) consequences of main results are also discussed.     

On Explicit Bounds in Picard's Theorem and Schottky's Theorem

Let λ(τ)be the elliptic function.We define the function t∶(0,∞);→(0,∞) byλ(1 it(α))=-α.The functiorl t(α)is a decreasing functiorl of a with t(1)= 1.In the following we need the function g(a)=ae~(πt).Let S denote the class of functions which are analytic in the unit disc D and omit 0 and 1.Schottky's theorem asserts the existence of a function K(α,γ)sueh that     

平面上具有有界Fréchet导数的调和映照单叶半径的精确估计

给定单位圆盘D={z||z|1}上调和映照f(z)=h(z)+g(z),其中h(z)和g(z)为D上的解析函数,满足f(0)=0,λf(0)=1,ΛfΛ.通过引入复参数λ,|λ|=1,本文研究调和映照Fλ(z)=h(z)+λg(z)和解析函数Gλ(z)=h(z)+λg(z)的性质,得到Fλ(z)和Gλ(z)单叶半径的精确估计.作为应用,本文得到单位圆盘D上某些K-拟正则调和映照Bloch常数的更好估计,改进和推广由Chen等人所得的相应结果.     

A new class of Salagean-type harmonic univalent functions

We define and investigate a new class of Salagean-type harmonic univalent functions. We obtain coefficient conditions, extreme points, distortion bounds, convex combination and radii of convex for the above class of harmonic univalent functions.     

一类解析函数族及其α阶组合问题

引进用 Hλ算子刻画的一族解析函数 Pn(λ,α,β,ρ)并研究族 Pn(λ,α,β,ρ)上算子函数及其导数的α阶组合问题 .得到用α阶组合定义的函数在圆域 |Z|相似文献   

On the Fekete-Szegö problem for concave univalent functions

We consider the Fekete-Szegö problem with real parameter λ for the class Co(α) of concave univalent functions.     

Hilbert空间中具有正算子系数的亚纯单叶算子值函数

本文讨论了Hilbert空间中具有正算子系数的亚纯单叶算子值函数集Σ[α，β]，得到了f(z)∈Σ[α，β]的充要条件及算子系数估计，并表明在算术平均及凸线性组合下Σ[α，β]是闭的．     

用Salagean算子定义的缺系数的单叶调和函数类

本文研究了用Salagean算子定义的缺系数单叶调和函数类.利用从属关系和算子理论得到类中函数的系数估计、极值点、偏差定理、卷积性质、凸性组合与凸半径,推广了已有的一些结果.     

實向量所成的有序環

<正> 引言 本文討論G.Birkhoff在“格論”第二版中所提出的一個未解决的問題(見参考文獻[1]229頁問題103).這個問題是: 合G為所有賓2維向量(a,b)所成的集合.在向量加法之下,G形成一交換羣.若在G中如下定義順序關係“≧”     

A CLASS OF HARMONIC STARLIKE FUNCTIONS WITH RESPECT TO SYMMETRIC POINTS ASSOCIATED WITH WRIGHT GENERALIZED HYPERGEOMETRIC FUNCTION

Making use of Wright operator we introduce a new class of complex-valued harmonic functions with respect to symmetric points which are orientation preserving, univalent and starlike. We obtain coefficient conditions, extreme points, distortion bounds, and convex combination.