Communications of the
Korean Mathematical Society

ISSN(Print) 1225-1763 ISSN(Online) 2234-3024



Commun. Korean Math. Soc. 2022; 37(4): 1025-1039

Online first article September 21, 2022      Printed October 31, 2022

Copyright © The Korean Mathematical Society.

On functions starlike with respect to $n$-ply symmetric, conjugate and symmetric conjugate points

Somya Malik, Vaithiyanathan Ravichandran

National Institute of Technology; National Institute of Technology


For given non-negative real numbers $\alpha_k$ with $ \sum_{k=1}^{m}\alpha_k =1$ and normalized analytic functions $f_k$, $k=1,\dotsc,m$, defined on the open unit disc, let the functions $F$ and $F_n$ be defined by $ F(z):=\sum_{k=1}^{m}\alpha_k f_k (z)$, and $F_{n}(z):=n^{-1}\sum_{j=0}^{n-1} e^{-2j\pi i/n} F(e^{2j\pi i/n} z)$. This paper studies the functions $f_k$ satisfying the subordination $zf'_{k} (z)/F_{n} (z) \prec h(z)$, where the function $h$ is a convex univalent function with positive real part. We also consider the analogues of the classes of starlike functions with respect to symmetric, conjugate, and symmetric conjugate points. Inclusion and convolution results are proved for these and related classes. Our classes generalize several well-known classes and the connections with the previous works are indicated.

Keywords: Starlike functions, convex functions, symmetric points, conjugate points, convolution

MSC numbers: 30C80, 30C45

Supported by: The first author is supported by the UGC-JRF Scholarship.