On univalent functions, Bloch functions and VMOA

1978 ◽  
Vol 236 (3) ◽  
pp. 199-208 ◽  
Author(s):  
Ch. Pommerenke
1988 ◽  
Vol 35 (2) ◽  
pp. 313-320 ◽  
Author(s):  
J. M. Anderson ◽  
L. D. Pitt

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Fernando Pérez-González ◽  
Jouni Rättyä

It is shown that a univalent functionfbelongs toQKif and only ifsup a∈𝔻∫01M∞2(r,f∘φa-f(a))K′(log (1/r))dr<∞, whereφa(z)=(a-z)/(1-a¯z), providedKsatisfies certain regularity conditions. It is also shown that under these conditionsQKcontains all univalent Bloch functions if and only if∫01(log ((1+r)/(1-r)))2K′(log (1/r))dr<∞.


2015 ◽  
Vol 4 (4) ◽  
pp. 28-33
Author(s):  
Dr. T. Ram Reddy ◽  
◽  
R. Bharavi Sharma ◽  
K. Rajya Lakshmi ◽  
◽  
...  

Author(s):  
Deepali Khurana ◽  
Raj Kumar ◽  
Sibel Yalcin

We define two new subclasses, $HS(k, \lambda, b, \alpha)$ and \linebreak $\overline{HS}(k, \lambda, b, \alpha)$, of univalent harmonic mappings using multiplier transformation. We obtain a sufficient condition for harmonic univalent functions to be in $HS(k,\lambda,b,\alpha)$ and we prove that this condition is also necessary for the functions in the class $\overline{HS} (k,\lambda,b,\alpha)$. We also obtain extreme points, distortion bounds, convex combination, radius of convexity and Bernandi-Libera-Livingston integral for the functions in the class $\overline{HS}(k,\lambda,b,\alpha)$.


2020 ◽  
Vol 26 (1) ◽  
pp. 111-115
Author(s):  
Janusz Sokół ◽  
Katarzyna Trabka-Wiȩcław

AbstractThis paper considers the following problem: for what value r, {r<1} a function that is univalent in the unit disk {|z|<1} and convex in the disk {|z|<r} becomes starlike in {|z|<1}. The number r is called the radius of convexity sufficient for starlikeness in the class of univalent functions. Several related problems are also considered.


Axioms ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Hari Mohan Srivastava ◽  
Ahmad Motamednezhad ◽  
Safa Salehian

In this paper, we introduce a new comprehensive subclass ΣB(λ,μ,β) of meromorphic bi-univalent functions in the open unit disk U. We also find the upper bounds for the initial Taylor-Maclaurin coefficients |b0|, |b1| and |b2| for functions in this comprehensive subclass. Moreover, we obtain estimates for the general coefficients |bn|(n≧1) for functions in the subclass ΣB(λ,μ,β) by making use of the Faber polynomial expansion method. The results presented in this paper would generalize and improve several recent works on the subject.


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