In this paper,we introduce the subfamilies Hm(RIV(n))of holomorphic mappings defined on the Lie ball RIV(n)which reduce to the family of holomorphic mappings and the family of locally biholomorphic mappings when m=1 and m→+∞,respectively.Various distortion theorems for holomophic mappings Hm(RIV(n))are established.The distortion theorems coincide with Liu and Minda’s as the special case of the unit disk.When m=1 and m→+∞,the distortion theorems reduce to the results obtained by Gong for RIV(n),respectively.Moreover,our method is different.As an application,the bounds for Bloch constants of Hm(RIV(n))are given.
WANG JianFei1,LIU TaiShun2 &XU HuiMing1 1College of Mathematics,Physics and Information Engineering,Zhejiang Normal University,Jinhua 321004, China 2D epartment of Mathematics,Huzhou Teachers College,Huzhou 313000,China
In this article, we establish distortion theorems for some various subfamilies of Bloch mappings defined in the unit polydisc Dn with critical points, which extend the results of Liu and Minda to higher dimensions. We obtain lower bounds of ｜ det（f＇（z））｜and Rdet（f＇（z）） for Bloch mapping f. As an application, some lower and upper bounds of Bloch constants for the subfamilies of holomorphic mappings are given.
Liczberski-Starkov firstfound a lower bound for ｜｜D（f）｜｜ near the origin, where f（z）=（F（z1）,√F1（z1）z2,…,√F＇（z1）zn）＇is the Roper-Suffridge operator on the unit ball Bn in Cn and F is a normalized convex function on the unit disk. Later, Liczberski-Starkov and Hamada-Kohr proved the lower bound holds on the whole unit ball using a complex computation. Here we provide a rather short and easy proof for the lower bound. Similarly, when F is a normalized starlike function on the unit disk, a lower bound of ｜｜D（f）｜｜ is obtained again.
In this paper, we obtain a version of subordination lemma for hyperbolic disk relative to hyperbolic geometry on the unit disk D. This subordination lemma yields the distortion theorem for Bloch mappings f ∈ H（B^n） satisfying ｜｜f｜｜0 = 1 and det f＇（0） = α ∈ （0, 1], where｜｜f｜｜0 = sup{（1 - ｜z｜^2 ）n＋1/2n det（f＇（z））[1/n ： z ∈ B^n}. Here we establish the distortion theorem from a unified perspective and generalize some known results. This distortion theorem enables us to obtain a lower bound for the radius of the largest univalent ball in the image of f centered at f（0）. When a = 1, the lower bound reduces to that of Bloch constant found by Liu. When n = 1, our distortion theorem coincides with that of Bonk, Minda and Yanagihara.
