J. Korean Math. Soc. 2012; 49(4): 671-686
Printed July 1, 2012
https://doi.org/10.4134/JKMS.2012.49.4.671
Copyright © The Korean Mathematical Society.
Li-Mei Wang
Tohoku University
This paper mainly deals with the tilted Carath{\'e}odory class by angle $\lambda\in(-\pi/2,\pi/2)$ (denoted by $\mathcal{P}_{\lambda}$) an element of which maps the unit disc into the tilted right half-plane $\{w: \Re e^{i\lambda} w>0\}$. Firstly we will characterize $\mathcal{P}_{\lambda}$ from different aspects, for example by subordination and convolution. Then various estimates of functionals over $\mathcal{P}_{\lambda}$ are deduced by considering these over the extreme points of $\mathcal{P}_{\lambda}$ or the knowledge of functional analysis. Finally some subsets of analytic functions related to $\mathcal{P}_{\lambda}$ including close-to-convex functions with argument $\lambda$, $\lambda$-spirallike functions and analytic functions whose derivative is in $\mathcal{P}_{\lambda}$ are also considered as applications.
Keywords: the tilted Carath{\'e}odory class, $\lambda$-spirallike functions, close-to-convex functions with argument $\lambda$, convolution, subordination
MSC numbers: Primary 30C45; Secondary 30C70
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