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JOURNALS // Sibirskii Matematicheskii Zhurnal // Archive

Sibirsk. Mat. Zh., 2016 Volume 57, Number 4, Pages 768–775 (Mi smj2783)

This article is cited in 12 papers

On subordination of some analytic functions

R. Kargara, A. Ebadianb, J. Sokółc

a Young Researchers and Elite Club, Urmia Branch, Islamic Azad University, Urmia, Iran
b Department of Mathematics, Payame Noor University, P.O. Box 19395–3697 Tehran, Iran
c Department of Mathematics, Rzeszów University of Technology, Rzeszów, Poland

Abstract: We define $\mathscr V(\alpha,\beta)$ ($alpha<1$ and $\beta>1$), the new subclass of analytic functions with bounded positive real part,
$$ \mathscr V(\alpha,\beta)^=\Bigl\{f\in\mathscr A\colon\alpha<\operatorname{Re}\Bigl\{\Bigl(\frac z{f(z)}\Bigr)^2f'(z)\Bigr\}<\beta\Bigr\}, $$
and study some properties of $\mathscr V(\alpha,\beta)$. We also study the class $\mathscr U(\gamma)$ ($\gamma>0$):
$$ \mathscr U(\gamma):=\Bigl\{f\in\mathscr A\colon\Bigl|\Bigl(\frac z{f(z)}\Bigr)^2f'(z)-1\Bigr|<\gamma\Bigr\}, $$
where $\mathscr A$ is the class of normalized functions.

Keywords: analytic function, subordination, bounded positive real part, Fekete–Szegö problem.

UDC: 517.53

Received: 02.02.2015

DOI: 10.17377/smzh.2016.57.404


 English version:
Siberian Mathematical Journal, 2016, 57:4, 599–605

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