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Bohr's classical theorem and its generalizations are now active areas of research and have been the source of investigations in numerous function spaces. In this article, we study a generalized Bohr's inequality for the class of bounded…

Complex Variables · Mathematics 2022-05-04 Shankey Kumar

The primary objective of this paper is to establish several sharp versions of improved Bohr inequalities, refined Bohr inequalities, and Bohr-Rogosinski inequalities for the class of $K$-quasiconformal sense-preserving harmonic mappings…

Complex Variables · Mathematics 2024-11-27 Vasudevarao Allu , Raju Biswas , Rajib Mandal

We study the localization of the poles of the best Mobius approximations for locally univalent functions in the unit disk. Sharp geometric bounds for the pole function are established in terms of Pommerenke's linear invariant orders,…

Complex Variables · Mathematics 2025-10-24 Hugo Arbelaez , Martin Chuaqui , Rodrigo Hernandez , Willy Sierra

We prove sharp inequalities for the symmetric-decreasing rearrangement in Fourier space of functions in $\mathbb{R}^d$. Our main result can be applied to a general class of (pseudo-)differential operators in $\mathbb{R}^d$ of arbitrary…

Analysis of PDEs · Mathematics 2019-03-06 Enno Lenzmann , Jérémy Sok

Slice regular functions are a generalization of holomorphic functions to the setting of quaternions (and more generally, Clifford algebras). In this paper, we first establish the Bohr inequality for slice starlike functions and slice…

Complex Variables · Mathematics 2025-11-18 Sabir Ahammed , Molla Basir Ahamed , Ming-Sheng Liu

We provide sufficient conditions for the existence of a strong derivable map and calculate its derivative by employing a result in our previous work on strong derivability of maps arising by functional calculus of an unbounded scalar type…

Functional Analysis · Mathematics 2025-02-11 Benedetto Silvestri

In this article,we first give a modified Schwarz-Pompeiu formula in a general sector ring by proper conformal mappings, and obtain the solution of the Schwarz problem for the Cauchy-Riemann equation in explicit forms. Furthermore, a class…

Complex Variables · Mathematics 2022-02-01 Zhihua Du , Ying Wang , Min Ku

A pre-Schwarzian and a Schwarzian derivative for locally univalent pluriharmonic mappings in ${\mathbb C}^n$ are introduced. Basic properties such as the chain rule, multiplicative invariance and affine invariance are proved for these…

Complex Variables · Mathematics 2020-10-19 Iason Efraimidis , Álvaro Ferrada-Salas , Rodrigo Hernández , Rodrigo Vargas

For analytic functions in the unit disk, general bounds on the Schwarzian derivative in terms of Nehari functions are shown to imply uniform local univalence and in some cases finite and bounded valence. Similar results are obtained for the…

Complex Variables · Mathematics 2019-05-01 M. Chuaqui , P. Duren , B. Osgood

For $r > 0$ and integers $t \ge n > 0$, we consider the following problem: maximize the amplitude $|x_t|$ at time $t$, over all complex solutions $x = (x_0, x_1, \dots)$ of arbitrary homogeneous linear difference equations of order $n$ with…

Complex Variables · Mathematics 2025-08-21 Dmitrii M. Ostrovskii , Pavel S. Shcherbakov

In this paper, by using the rotation method, we calculate that the sharp bound for $n$-dimensional Hardy operator $\mathcal{H}$ on mixed radial-angular spaces. Furthermore, we also obtain the sharp bound for $n$-dimensional fractional Hardy…

Classical Analysis and ODEs · Mathematics 2022-08-01 Mingquan Wei , Dunyan Yan

Discrete mathematics, the study of finite structures, is one of the fastest growing areas in mathematics and optimization. Discrete fractional calculus (DFC) theory that is an important subject of the fractional calculus includes the…

Classical Analysis and ODEs · Mathematics 2018-03-15 Okkes Ozturk

We investigate a class of nonlocal integro-differential equations involving Hilfer fractional derivatives and almost sectorial operators. We prove existence results by applying Schauder's fixed point technique. Moreover, we show fundamental…

Spectral Theory · Mathematics 2021-03-09 Kulandhaivel Karthikeyan , Amar Debbouche , Delfim F. M. Torres

In this article we establish Bohr inequalities for operator valued functions, which can be viewed as the analogues of a couple of interesting results from scalar valued settings. Some results of this paper are motivated by the classical…

Complex Variables · Mathematics 2021-01-12 Bappaditya Bhowmik , Nilanjan Das

This paper is devoted to the study of general (Laurent) polynomial modifications of moment functionals on the unit circle, i.e., associated with hermitian Toeplitz matrices. We present a new approach which allows us to study polynomial…

Classical Analysis and ODEs · Mathematics 2009-08-19 M. J. Cantero , L. Moral , L. Velazquez

The classical Bohr theorem and its subsequent generalizations have become active areas of research, with investigations conducted in numerous function spaces. Let $\{\psi_n(r)\}_{n=0}^\infty$ be a sequence of non-negative continuous…

Complex Variables · Mathematics 2026-04-14 Raju Biswas , Rajib Mandal

For a function $f$ from the Sobolev space $W^{1,p}(C)$ ($C\subset\mathbb{R}^d$ is an open convex cone), a sharp inequality that estimates $\| f\|_{L_{\infty}}$ via the $L_{p}$-norm of its gradient and a seminorm of the function is obtained.…

Functional Analysis · Mathematics 2025-03-18 V. F. Babenko , V. V. Babenko , O. V. Kovalenko , N. V. Parfinovych

In this article, we first establish a generalized Bohr inequality and examine its sharpness for a class of analytic functions $f$ in a simply connected domain $\Omega_\gamma,$ where $0\leq \gamma<1$ with a sequence $\{\varphi_n(r)…

Complex Variables · Mathematics 2024-05-06 Sabir Ahammed , Molla Basir Ahamed , Partha Pratim Roy

We prove several sharp distortion and monotonicity theorems for spherically convex functions defined on the unit disk involving geometric quantities such as spherical length, spherical area and total spherical curvature. These results can…

Complex Variables · Mathematics 2022-04-05 Maria Kourou , Oliver Roth

We prove functional inequalities in any dimension controlling the iterated derivatives along a transport of the Coulomb or super-Coulomb Riesz modulated energy in terms of the modulated energy itself. This modulated energy was introduced by…

Analysis of PDEs · Mathematics 2025-10-29 Matthew Rosenzweig , Sylvia Serfaty