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Related papers: Bohr inequality for odd analytic functions

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We prove that if $(\varphi_n)_{n=0}^\infty, \; \varphi_0 \equiv 1, $ is a basis in the space of entire functions of $d$ complex variables, $d\geq 1,$ then for every compact $K\subset \mathbb{C}^d$ there is a compact $K_1 \supset K$ such…

Complex Variables · Mathematics 2014-02-26 Aydin Aytuna , Plamen Djakov

We consider the class of all analytic and locally univalent functions $f$ of the form $f(z)=z+\sum_{n=2}^\infty a_{2n-1} z^{2n-1}$, $|z|<1$, satisfying the condition $$ {\rm Re}\,\left(1+\frac{zf^{\prime\prime}(z)}{f^\prime…

Complex Variables · Mathematics 2016-04-20 Sarita Agrawal , Swadesh Kumar Sahoo

In this article, we study the Bohr type inequality for {C}es\'{a}ro operator and {B}ernardi integral operator acting on the space of analytic functions defined on a simply connected domain containing the unit disk $\mathbb{D}$.

Complex Variables · Mathematics 2022-02-15 Vasudevarao Allu , Nirupam Ghosh

In this article, we present some new inequalities for numerical radius of Hilbert space operators via convex functions. Our results generalize and improve earlier results by El-Haddad and Kittaneh. Among several results, we show that if…

Functional Analysis · Mathematics 2019-07-16 S. Tafazoli , H. R. Moradi , S. Furuichi , P. Harikrishnan

Given a complex domain $\Omega$ and analytic functions $\varphi_1,\ldots,\varphi_n : \Omega \to \mathbb{D}$, we give geometric conditions for $H^\infty(\Omega)$ to be generated by functions of the form $g \circ \varphi_k$, $g \in…

Complex Variables · Mathematics 2017-03-22 Michael A. Dritschel , Daniel Estévez , Dmitry Yakubovich

We investigate harmonic mappings $f=h+\bar{g}$ defined in the unit disk, where $g$ and $h$ satisfy certain prescribed conditions and the analytic part $h$ belongs to the Ma and Minda class of starlike functions. Certain sharp radius results…

Complex Variables · Mathematics 2022-08-02 Kamaljeet Gangania

Let $f$ be a complex-valued harmonic mapping defined in the unit disk $\mathbb D$. We introduce the following notion: we say that $f$ is a Bloch-type function if its Jacobian satisfies $$ \sup_{z\in\mathbb D}(1-|z|^2)\sqrt{|J_f(z)|}<\infty.…

Complex Variables · Mathematics 2016-12-26 I. Efraimidis , J. Gaona , R. Hernández , O. Venegas

In this article, the new inequalities for the weighted sums of coefficients in the class of bounded functions in the disk are obtained. We develop the methods of I.R.~Kayumov and S.~Ponnusamy, using E.~Reich's theorem on the majorization of…

Complex Variables · Mathematics 2025-03-21 Ramis Sh. Khasianov

We study generalized Poincar\'e inequalities. We prove that if a function satisfies a suitable inequality of Poincar\'e type, then the Hardy-Littlewood maximal function also obeys a meaningful estimate of similar form. As a by-product, we…

Classical Analysis and ODEs · Mathematics 2021-02-23 Olli Saari

The Bohr radius for power series of holomorphic functions mapping a multidimensional Reinhardt domain into the convex domain in the complex plane is independent of this convex domain.

Complex Variables · Mathematics 2007-05-23 Lev Aizenberg

The main purpose of this paper is to determine the radii of starlikeness and convexity of the generalized $\emph{k}-$Bessel functions for three different kinds of normalization by using their Hadamard factorization in such a way that the…

Complex Variables · Mathematics 2019-03-06 Evrim Toklu

In this paper, we introduce a family of analytic functions given by $$\psi_{A,B}(z):= \dfrac{1}{A-B}\log{\dfrac{1+Az}{1+Bz}},$$ which maps univalently the unit disk onto either elliptical or strip domains, where either $A=-B=\alpha$ or…

Complex Variables · Mathematics 2022-09-12 S. Sivaprasad Kumar , Pooja Yadav

The classical inequality of Bohr asserts that if a power series converges in the unit disk and its sum has modulus less than or equal to $1$, then the sum of absolute values of its terms is less than or equal to $1$ for the subdisk…

Complex Variables · Mathematics 2020-06-12 Saminathan Ponnusamy , Ramakrishnan Vijayakumar , Karl-Joachim Wirths

Based on a generalization of Bohr's equivalence relation for general Dirichlet series, in this paper we study the sets of values taken by certain classes of equivalent almost periodic functions in their strips of almost periodicity. In…

Complex Variables · Mathematics 2018-01-11 J. M. Sepulcre , T. Vidal

The main aim of this article is to establish a sharp improvement of the classical Bohr inequality for bounded holomorphic mappings in the polydisk $\mathbb{P}\Delta(0;1_n)$. We also prove two other sharp versions of the Bohr inequality in…

Complex Variables · Mathematics 2025-12-09 Molla Basir Ahamed , Sujoy Majumder , Nabadwip Sarkar , Ming-Sheng Liu

Given two arbitrary almost periodic functions with associated Fourier exponents which are linearly independent over the rational numbers, we prove that the existence of a common open vertical strip $V$, where both functions assume the same…

Classical Analysis and ODEs · Mathematics 2021-05-04 M. Righetti , J. M. Sepulcre , T. Vidal

We prove a sharpened version of the Strichartz inequality for radial solutions of the Schr\"odinger equation in $\mathbb{R}^2\times \mathbb{R}$. We establish an improved upper bound for functions that nearly extremize the inequality, with a…

Classical Analysis and ODEs · Mathematics 2018-07-26 Felipe Gonçalves

We consider a fourth order partial differential equation in n-dimensional space introduced by Abreu in the context of K\"{a}hler metrics on toric orbifolds. Similarity solutions depending only on the radial coordinate in R^n are determined…

Differential Geometry · Mathematics 2007-05-23 A. N. W. Hone

We consider some second order quasilinear partial differential inequalities for real valued functions on the unit ball and find conditions under which there is a lower bound for the supremum of nonnegative solutions that do not vanish at…

Complex Variables · Mathematics 2009-07-21 Adam Coffman , Yifei Pan

Some geometric properties of a normalized hyper-Bessel functions are investigated. Especially we focus on the radii of starlikeness, convexity, and uniform convexity of hyper-Bessel functions and we show that the obtained radii satisfy some…

Complex Variables · Mathematics 2021-01-19 İbrahim Aktaş , Árpád Baricz , Sanjeev Singh
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