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Let $E$ be a subset of the unit disc $U$ of the complex plane $\CC$. Recall that $H^p(U)$ is the space of all holomorphic functions $g$ on $U$ for which $\|g\|_{H^p}$ $<$ $\infty$. Put \begin{equation} C_p(\epsilon, R) = \sup \{\sup_{|z|…

Complex Variables · Mathematics 2007-05-23 Dang Duc Trong , Truong Trung Tuyen

We obtain Gr\"onwall type estimates for the gradient of the harmonic functions for a L\'evy operator with order strictly larger than 1 and minimal assumptions of its L\'evy measure.

Analysis of PDEs · Mathematics 2022-08-02 Tomasz Grzywny , Tomasz Jakubowski , Grzegorz Żurek

We consider a class of stochastic processes and establish its connection to $p$-harmonic functions. In particular, we obtain stochastic approximations that converge uniformly to a $p$-harmonic function, with an explicit convergence rate,…

Analysis of PDEs · Mathematics 2016-05-19 Hannes Luiro , Mikko Parviainen

The boundedness of compactness of integral-type operators from Hardy space to Bloch space on the upper half-plane $\Pi_+=\{z\in\mathbb{C}:Imz>0\}$ are characterized.

Complex Variables · Mathematics 2012-12-10 Xu Ning

It is known that a subharmonic function of finite order $\rho$ can be approximated by the logarithm of the modulus of an entire function at the point $z$ outside an exceptional set up to $C\log|z|$. In this article we prove that if such an…

Complex Variables · Mathematics 2007-10-03 Markiyan Hirnyk

In this article, Bohr type inequalities for some complex valued harmonic functions defined on the unit disk are given. All the results are sharp.

Complex Variables · Mathematics 2025-02-06 Jianying Zhou , Wanqing Hou , Boyong Long

This paper considers optimization of smooth nonconvex functionals in smooth infinite dimensional spaces. A H\"older gradient descent algorithm is first proposed for finding approximate first-order points of regularized polynomial…

Optimization and Control · Mathematics 2021-04-07 Serge Gratton , Sadok Jerad , Philippe L. Toint

We prove a sharp Hardy inequality for fractional integrals for functions that are supported on a general domain. The constant is the same as the one for the half-space and hence our result settles a recent conjecture of Bogdan and Dyda.

Analysis of PDEs · Mathematics 2010-02-22 Michael Loss , Craig Sloane

In this expository paper we collect many recent advances in analytic function spaces of several complex variables related with trace problem. We consider various function space of analytic functions of several variables in various domains…

Complex Variables · Mathematics 2025-09-24 Romi F. Shamoyan , Nataliya M. Makhina

We construct sense-preserving univalent harmonic mappings which map the unit disk onto a domain which is convex in the horizontal direction, but with varying dilatation. Also, we obtain minimal surfaces associated with such harmonic…

Complex Variables · Mathematics 2015-08-04 YuePing Jiang , ZhiHong Liu , Saminathan Ponnusamy

For analytic functions $g$ on the unit disc with non-negative Maclaurin coefficients, we describe the boundedness and compactness of the integral operator $T_g(f)(z)=\int_0^zf(\zeta)g'(\zeta)\,d\zeta$ from a space $X$ of analytic functions…

Complex Variables · Mathematics 2021-03-17 José Ángel Peláez , Jouni Rättyä , Fanglei Wu

We generalize a classical result by A.Macintyre and W.Rogosinski on best $H^p$--approximation in $L^p$ of rational functions. For each inner function $\theta$ we give a description of $H^p$--badly approximable functions in $\bar \theta…

Complex Variables · Mathematics 2013-09-26 R. V. Bessonov

In this paper, we prove necessary and sufficient conditions for a sense-preserving harmonic function to be absolutely convex in the open unit disk. We also estimate the coefficient bound and obtain growth, covering and area theorems for…

Complex Variables · Mathematics 2016-05-10 Saminathan Ponnusamy , Anbareeswaran Sairam Kaliraj , Victor V. Starkov

In this note, we aim to describe sharp constants for the composition operator with a bi-Lipschitz measure-preserving map in several functional spaces (BMO, Hardy space, Carleson measures, ...). It is interesting to see how the measure…

Classical Analysis and ODEs · Mathematics 2012-04-27 Frederic Bernicot , Sahbi Keraani

We provide some new sharp embeddings for p-Carleson and related measures in the unit disk of the complex plane

Complex Variables · Mathematics 2012-02-21 Romi Shamoyan , Ali Abkar

We consider a version of M. Riesz fractional integral operator on a space of homogeneous type and show an analogue of the well-known Hardy--Littlewood--Sobolev theorem in this context. In our main result, we investigate the dependence of…

Classical Analysis and ODEs · Mathematics 2012-12-14 Anna Kairema

We study various properties of the gradients of solutions to harmonic functions on Lipschitz surfaces. We improve an exponential bound of Naber and Valtorta on the size of the superlevel sets for the frequency function to a sharp quadratic…

Analysis of PDEs · Mathematics 2024-03-05 Benjamin Foster

We use the Hardy spaces for Fourier integral operators to obtain bounds for spherical maximal functions in $L^{p}(\mathbb{R}^{n})$, $n\geq2$, where the radii of the spheres are restricted to a compact interval in $(0,\infty)$. These bounds…

Classical Analysis and ODEs · Mathematics 2026-02-24 Abhishek Ghosh , Naijia Liu , Jan Rozendaal , Liang Song

We compute the explicit sharp constants of Hardy inequalities in the cone $\mathbb{R}_{k_+}^{n}:=\mathbb{R}^{n-k}\times (\mathbb{R}_{+})^{k}=\{(x_{1},...,x_{n})|x_{n-k+1}>0,...,x_{n}>0\}$ with $1\leq k\leq n$. Furthermore, the spherical…

Functional Analysis · Mathematics 2011-11-17 Dan Su , Qiao-Hua Yang

Let ${\mathcal S}$ denote the set of all univalent analytic functions $f(z)=z+\sum_{n=2}^{\infty}a_n z^n$ on the unit disk $|z|<1$. In 1946 B. Friedman found that the set $\mathcal S$ of those functions which have integer coefficients…

Complex Variables · Mathematics 2012-07-17 S. Ponnusamy , J. Qiao