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Let $\mathcal{A}$ be the family of functions $f(z)=z+a_2z^2+...$ which are analytic in the open unit disc $\mathbb{D}=\{z: |z|<1 \}$, and denote by $\pe$ of functions $p(z)=z+p_1z+p_2z^2+...$ analytic in $\de$ such that $p(z)$ is in $\pe$…

Complex Variables · Mathematics 2017-05-04 Yaşar Polatoğlu , Yasemin Kahramaner , Arzu Yemişçi Şen

In this paper, we show that the Carath\'{e}odory function $\varphi_{\scriptscriptstyle {Ne}}(z)=1+z-z^3/3$ maps the open unit disk $\mathbb{D}$ onto the interior of the nephroid, a $2$-cusped kidney-shaped curve, \begin{align*}…

Complex Variables · Mathematics 2021-04-13 Lateef Ahmad Wani , A. Swaminathan

Radius constants for several classes of analytic functions on the unit disk are obtained. These include the radius of starlikeness of a positive order, radius of parabolic starlikeness, radius of Bernoulli lemniscate starlikeness, and…

Complex Variables · Mathematics 2012-10-18 Rosihan M. Ali , Naveen Jain , V. Ravichandran

By considering the polynomial function $\phi_{car}(z)=1+z+z^2/2,$ we define the class $\Scar$ consisting of normalized analytic functions $f$ such that $zf'/f$ is subordinate to $\phi_{car}$ in the unit disk. The inclusion relations and…

Complex Variables · Mathematics 2020-12-29 Prachi Gupta , Sumit Nagpal , V. Ravichandran

This survey mainly deals with the tilted Carath{\'e}odory class by angle $\lambda$ (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…

Complex Variables · Mathematics 2010-06-30 Li-Mei Wang

In the present investigation, we study the class of Sigmoid starlike functions, given by $\mathcal{S}^*_{SG}=\{f\in\mathcal{A}: {zf'(z)}/{f(z)}\prec 2/(1+e^{-z})\}$ in context of estimating the sharp radius constants associated with several…

Complex Variables · Mathematics 2022-08-03 Priyanka Goel , S. Sivaprasad Kumar

A normalized analytic function f defined on the open unit disk in the complex plane is in the class SL if zf'(z)/f(z) lies in the region bounded by the right-half of the lemniscate of Bernoulli given by |w^2 - 1| < 1. In the present…

Complex Variables · Mathematics 2012-01-09 Rosihan M. Ali , Naveen Jain , V. Ravichandran

In the past several subclasses of starlike functions are defined involving real part and modulus of certain expressions of functions under study, combined by way of an inequality. In the similar fashion, we introduce a new class…

Complex Variables · Mathematics 2021-08-25 S. Sivaprasad Kumar , Shagun Banga

We determine the Bohr radius for the class of odd functions $f$ satisfying $|f(z)|\le 1$ for all $|z|<1$, settling the recent conjecture of Ali, Barnard and Solynin \cite{AliBarSoly}. In fact, we solve this problem in a more general…

Complex Variables · Mathematics 2017-01-17 Ilgiz R Kayumov , Saminathan Ponnusamy

We introduce and study a class of starlike functions defined by \begin{equation*} \mathscr{S}^*_\wp:=\left\{f\in\mathcal{A}: \frac{zf'(z)}{f(z)}\prec 1+ze^z=:\wp(z)\right\}, \end{equation*} where $\wp$ maps the unit disk onto a cardioid…

Complex Variables · Mathematics 2022-08-23 S. Sivaprasad Kumar , Kamaljeet Gangania

Let $\ID$ denote the open unit disk and $f:\,\ID\TO\BAR\IC$ be meromorphic and univalent in $\ID$ with the simple pole at $p\in (0,1)$ and satisfying the standard normalization $f(0)=f'(0)-1=0$. Also, let $f$ have the expansion…

Complex Variables · Mathematics 2010-08-31 Bappaditya Bhowmik , Saminathan Ponnusamy

This paper mainly uses the nonnegative continuous function $\{\zeta_n(r)\}_{n=0}^{\infty}$ to redefine the Bohr radius for the class of analytic functions satisfying $\real f(z)<1$ in the unit disk $|z|<1$ and redefine the Bohr radius of…

Complex Variables · Mathematics 2021-06-22 Rou-Yuan Lin , Ming-Sheng Liu , Saminathan Ponnusamy

Let ${\mathcal S}$ be the class of all functions $f$ that are analytic and univalent in the unit disk $\ID$ with the normalization $f(0)=f'(0)-1=0$. Let $\mathcal{U} (\lambda)$ denote the set of all $f\in {\mathcal S}$ satisfying the…

Complex Variables · Mathematics 2011-12-06 M. Obradović , S. Ponnusamy

We determine the Bohr radius for the class of all functions $f$ of the form $f(z)=\sum_{k=1}^\infty a_{kp+m} z^{kp+m}$ analytic in the unit disk $|z|<1$ and satisfy the condition $|f(z)|\le 1$ for all $|z|<1$. In particular, our result also…

Complex Variables · Mathematics 2017-08-21 Ilgiz R Kayumov , Saminathan Ponnusamy

Let $\mathcal{S}^*(\alpha_1,\alpha_2)$, where $ \alpha_1, \alpha_2 \in (0,1]$, represent the class of functions $f$ that are analytic in the open unit disk $\mathbb{D}$, normalized by $f(0) = f'(0) - 1=0$, and satisfying the following…

Complex Variables · Mathematics 2026-01-21 R. Kargar , J. Sokół , H. Mahzoon

In this paper we study the class $\mathcal{U}$ of functions that are analytic in the open unit disk ${\mathbb D}=\{z:|z|<1\}$, normalized such that $f(0)=f'(0)-1=0$ and satisfy \[\left|\left [\frac{z}{f(z)} \right]^{2}f'(z)-1…

Complex Variables · Mathematics 2018-12-24 Milutin Obradovic , Nikola Tuneski

For the family of analytic functions $f(z)$ in the open unit disk $\mathbb{D}$ with $f(0)=f'(0)-1=0$, satisfying the differential equation \begin{equation*} zf'(z) - f(z) = \dfrac{1}{2} z^2 \phi(z), \quad |\phi(z)| \leq 1, \end{equation*}…

Complex Variables · Mathematics 2024-06-21 Prachi Prajna Dash , Jugal Kishore Prajapat

In this article, we impose a new class of fractional analytic functions in the open unit disk. By considering this class, we define a fractional operator, which is generalized Salagean and Ruscheweyh differential operators. Moreover, by…

Complex Variables · Mathematics 2016-02-26 Zainab E. Abdulnaby , Rabha W. Ibrahim , Adem Kilicman

Let ${\mathcal A}$ denote the family of all functions $f$ analytic in the open unit disk $\ID$ with the normalization $f(0)=0= f'(0)-1$ and ${\mathcal S}$ be the class of univalent functions from ${\mathcal A}$. In this paper, we consider…

Complex Variables · Mathematics 2014-12-30 Á. Baricz , M. Obradović , S. Ponnusamy

In this paper, we consider the Ma-Minda classes of analytic functions $\mathcal{S}^{*}(\phi):= \{f\in \mathcal{A} : ({zf'(z)}/{f(z)}) \prec \phi(z) \}$ and $\mathcal{C}(\phi):= \{f\in \mathcal{A} : (1+{zf''(z)}/{f'(z)}) \prec \phi(z) \}$…

Complex Variables · Mathematics 2023-07-25 S. Sivaprasad Kumar , Kamaljeet Gangania