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ON SOME SUBCLASSES OF HARMONIC MAPPINGS

Published online by Cambridge University Press:  10 July 2019

NIRUPAM GHOSH
Affiliation:
Department of Mathematics, Indian Institute of Technology Kharagpur, Kharagpur 721 302, West Bengal, India email [email protected]
VASUDEVARAO ALLU*
Affiliation:
School of Basic Science, Indian Institute of Technology Bhubaneswar, Bhubaneswar 752 050, Odisha, India email [email protected]

Abstract

Let ${\mathcal{P}}_{{\mathcal{H}}}^{0}(M)$ denote the class of normalised harmonic mappings $f=h+\overline{g}$ in the unit disk $\mathbb{D}$ satisfying $\text{Re}\,(zh^{\prime \prime }(z))>-M+|zg^{\prime \prime }(z)|$, where $h^{\prime }(0)-1=0=g^{\prime }(0)$ and $M>0$. Let ${\mathcal{B}}_{{\mathcal{H}}}^{0}(M)$ denote the class of sense-preserving harmonic mappings $f=h+\overline{g}$ in the unit disk $\mathbb{D}$ satisfying $|zh^{\prime \prime }(z)|\leq M-|zg^{\prime \prime }(z)|$, where $M>0$. We discuss the coefficient bound problem, the growth theorem for functions in the class ${\mathcal{P}}_{{\mathcal{H}}}^{0}(M)$ and a two-point distortion property for functions in the class ${\mathcal{B}}_{{\mathcal{H}}}^{0}(M)$.

Type
Research Article
Copyright
© 2019 Australian Mathematical Publishing Association Inc. 

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