Title of article :
A new subclass of harmonic mappings with positive coefficients
Author/Authors :
Haghighi ، A. R. - Technical and Vocational University (TVU) , Asghary ، N. - Islamic Azad University, Central Tehran Branch , Sedghi ، A. - Islamic Azad University, Central Tehran Branch
Abstract :
Complexvalued harmonic functions that are univalent and sensepreserving in the open unit disk $U$ can be written as form $f =h+bar{g}$, where $h$ and $g$ are analytic in $U$. In this paper, we introduce the class $S_H^1(beta)$, where $1 lt;betaleq 2$, and consisting of harmonic univalent function $f = h+bar{g}$, where $h$ and $g$ are in the form $h(z) = z+sumlimits_{n=2}^infty |a_n|z^n$ and $g(z) =sumlimits_{n=2}^infty |b_n|bar z^n$ for which $$mathrm{Re}left{z^2(h’’(z)+g’’(z)) +2z(h’(z)+g’(z))(h(z)+g(z))(z1)right} lt;beta.$$ It is shown that the members of this class are convex and starlike. We obtain distortions bounds extreme point for functions belonging to this class, and we also show this class is closed under convolution and convex combinations.
Keywords :
Convex combinations , extreme points , harmonic starlike functions , harmonic univalent functions
Journal title :
Journal of Linear and Topological Algebra
Journal title :
Journal of Linear and Topological Algebra