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Related papers: The Schwarz-Pick lemma for slice regular functions

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Recently, it is proven that positive harmonic functions defined in the unit disc or the upper half-plane in $\mathbb{C}$ are contractions in hyperbolic metrics \cite{Markovic}. Furthermore, the same result does not hold in higher dimensions…

Complex Variables · Mathematics 2025-06-25 Zhenghua Xu , Ting Yu , Qinghai Huo

In this paper we establish several invariant boundary versions of the (infinitesimal) Schwarz-Pick lemma for conformal pseudometrics on the unit disk and for holomorphic selfmaps of strongly convex domains in $\mathbb C^N$ in the spirit of…

Complex Variables · Mathematics 2023-08-08 Filippo Bracci , Daniela Kraus , Oliver Roth

The theory of slice regular functions is nowadays widely studied and has found its elegant applications to a functional calculus for quaternionic linear operators and Schur analysis. However, much less is known about their boundary…

Complex Variables · Mathematics 2020-02-05 Guangbin Ren , Xieping Wang

In this paper, we prove a general Schwarz lemma at the boundary for holomorphic mappings from the polydisc to the unit ball in any dimensions. For the special case of one complex variable, the obtained results give the classic boundary…

Complex Variables · Mathematics 2014-11-04 Yang Liu , Zhihua Chen , Yifei Pan

We study several aspects concerning slice regular functions mapping the quaternionic open unit ball into itself. We characterize these functions in terms of their Taylor coefficients at the origin and identify them as contractive…

Complex Variables · Mathematics 2013-08-13 Daniel Alpay , Vladimir Bolotnikov , Fabrizio Colombo , Irene Sabadini

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

The purpose of this paper is to study the Schwarz-Pick type inequalities for harmonic or pluriharmonic functions. By analogy with the generalized Khavinson conjecture, we first give some sharp estimates of the norm of harmonic functions…

Complex Variables · Mathematics 2021-10-05 Shaolin Chen , Hidetaka Hamada

Let ${\mathcal S}$ be the class of analytic functions $f$ in the unit disk ${\mathbb D}$ with $f({\mathbb D}) \subset \overline{\mathbb D}$. Fix pairwise distinct points $z_1,\ldots,z_{n+1}\in \mathbb{D}$ and corresponding interpolation…

Complex Variables · Mathematics 2024-04-16 Gangqiang Chen

In this paper, we discuss some properties on hyperbolic-harmonic mappings in the unit ball of $\mathbb{C}^{n}$. First, we investigate the relationship between the weighted Lipschitz functions and the hyperbolic-harmonic Bloch spaces. Then…

Complex Variables · Mathematics 2012-05-01 Sh. Chen , S. Ponnusamy , X. Wang

In this paper we prove a quaternionic positive real lemma as well as its generalized version, in case the associated kernel has negative squares for slice hyperholomorphic functions. We consider the case of functions with positive real part…

Complex Variables · Mathematics 2018-10-16 D. Alpay , F. Colombo , I. Lewkowicz , I. Sabadini

Quantitative estimates are obtained for the (finite) valence of functions analytic in the unit disk with Schwarzian derivative that is bounded or of slow growth. A harmonic mapping is shown to be uniformly locally univalent with respect to…

Complex Variables · Mathematics 2007-07-16 Martin Chuaqui , Peter Duren , Brad Osgood

The theory of slice regular functions of a quaternionic variable on the unit ball of the quaternions was introduced by Gentili and Struppa in 2006 and nowadays it is a well established function theory, especially in view of its applications…

Functional Analysis · Mathematics 2023-06-22 José Oscar González-Cervantes , Juan Bory-Reyes , Irene Sabadini

Beginning in 2006, G. Gentili and D.C. Struppa developed a theory of regular quaternionic functions with properties that recall classical results in complex analysis. For instance, in each Euclidean ball centered at 0 the set of regular…

Complex Variables · Mathematics 2012-09-11 Caterina Stoppato

In this paper we prove two Bloch type theorems for quaternionic slice regular functions. We first discuss the injective and covering properties of some classes of slice regular functions from slice regular Bloch spaces and slice regular…

Complex Variables · Mathematics 2016-01-12 Zhenghua Xu , Xieping Wang

We first prove a Boundary Schwarz lemma for holomorphic disks on the unit ball in $\mathbb{C}^n$. Further by using a Schwarz lemma for minimal conformal disks of Forstneri\v c and Kalaj (F.~Forstneri{\v{c}} and D.~Kalaj. \newblock…

Complex Variables · Mathematics 2026-05-26 David Kalaj

The notion of a unitary realization is used to estimate derivatives of arbitrary order of functions in the Schur-Agler class on the polydisk and unit ball.

Complex Variables · Mathematics 2007-05-23 J. Milne Anderson , Michael A. Dritschel , James Rovnyak

We give simple proofs of various versions of the Schwarz lemma for real valued harmonic functions and for holomorphic (more generally harmonic quasi\-re\-gu\-lar, shortly HQR) mappings with the strip codomain. Along the way using the…

Complex Variables · Mathematics 2018-08-22 Miodrag Mateljević , Marek Svetlik

This article discusses classical versions of the Schwarz lemma at the boundary of the unit disk in the complex plane. The exposition includes commentary on the history, the mathematics, and the applications.

Complex Variables · Mathematics 2010-01-05 Harold P. Boas

Following ideas introduced by Beardon-Minda and by Baribeau-Rivard-Wegert in the context of the Schwarz-Pick lemma, we use the iterated hyperbolic difference quotients to prove a multipoint Julia lemma. As applications, we give a sharp…

Complex Variables · Mathematics 2021-01-12 Marco Abate

The Bloch-Landau Theorem is one of the basic results in the geometric theory of holomorphic functions. It establishes that the image of the open unit disc $\mathbb{D}$ under a holomorphic function $f$ (such that $f(0)=0$ and $f'(0)=1$)…

Complex Variables · Mathematics 2014-04-14 Chiara Della Rocchetta , Graziano Gentili , Giulia Sarfatti