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This note examines sufficient conditions for the quasiconformal extendibility of harmonic mappings defined in the unit disk. It is demonstrated that a harmonic strongly starlike mapping admits a quasiconformal extension to the entire plane,…

Complex Variables · Mathematics 2025-09-03 Xiu-Shuang Ma

It is shown that integral operators of the fully nonlinear type $K(x)(t)=\int_\Omega k(t,s,x(t),x(s))\,ds$ exhibit similar degeneracy phenomena in a large class of spaces as superposition operators $F(x)(t)=f(t,x(t))$. In particular, $K$ is…

Functional Analysis · Mathematics 2019-08-28 Martin Väth

We give a detailed description of the resolution of the identity of a second order $q$-difference operator considered as an unbounded self-adjoint operator on two different Hilbert spaces. The $q$-difference operator and the two choices of…

Classical Analysis and ODEs · Mathematics 2007-05-23 Erik Koelink , Jasper V. Stokman

We demonstrate the existence of quasiconformal mappings on closed manifolds that cannot be decomposed as a composition of mappings with arbitrarily small conformal distortion.

Geometric Topology · Mathematics 2026-05-22 Benjamin B. McMillan

This paper introduces the concept of quasi $\alpha$-firmly nonexpansive mappings in Wasserstein spaces over $\mathbb R^d$ and analyzes properties of these mappings. We prove that for quasi $\alpha$-firmly nonexpansive mappings satisfying a…

Functional Analysis · Mathematics 2025-03-11 Arian Bërdëllima , Gabriele Steidl

Given an analytic function $f=u+iv$ in the unit disk $\mathbb{D}$, Zygmund's theorem gives the minimal growth restriction on $u$ which ensures that $v$ is in the Hardy space $h^1$. This need not be true if $f$ is a complex-valued harmonic…

Complex Variables · Mathematics 2025-01-06 Suman Das , Jie Huang , Antti Rasila

In this paper we present an equivalent statement to the Jacobian conjecture. For a polynomial map F on an affine space of dimension n, we define recursively n finite sequences of polynomials. We give an equivalent condition to the…

Commutative Algebra · Mathematics 2016-01-05 Elzbieta Adamus , Pawel Bogdan , Teresa Crespo , Zbigniew Hajto

Avicou, Chalendar and Partington proved that an (unbounded) operator $(Af)=G\cdot f'$ on the classical Hardy space generates a $C_0$ semigroup of composition operators if and only if it generates a quasicontractive semigroup. Here we prove…

Functional Analysis · Mathematics 2019-08-01 Eva A. Gallardo-Gutiérrez , Dmitry Yakubovich

We identify the scaling limit of full-plane Kadanoff-Ceva fermions on generic, non-degenerate $s$-embeddings. In this broad setting, the scaling limits are described in terms of solutions to conjugate Beltrami equations with prescribed…

Probability · Mathematics 2025-12-24 Rémy Mahfouf

Tukia and Vaisala showed that every quasi-conformal map of $\R^n$ extends to a quasi-conformal self-map of $\R^{n+1}$. The restriction of the extended map to the upper half-space $\R^n \times \R^+$ is, in fact, bi-Lipschitz with respect to…

Geometric Topology · Mathematics 2013-05-23 Anton Lukyanenko

We investigate the distortion of Assouad dimension and the Assouad spectrum under Euclidean quasiconformal maps. Our results complement existing conclusions for Hausdorff and box-counting dimension due to Gehring--V\"ais\"al\"a and others.…

Complex Variables · Mathematics 2022-07-28 Efstathios Konstantinos Chrontsios Garitsis , Jeremy T. Tyson

In his monograph on Infinite Abelian Groups, I. Kaplansky raised three ``test problems" concerning their structure and multiplicity. As noted by Azoff, these problems make sense for any category admitting a direct sum operation. Here, we…

Functional Analysis · Mathematics 2023-06-21 Laurent W. Marcoux , Heydar Radjavi , Sascha Troscheit , Yuanhang Zhang

In the present paper we construct deformations of the Poincar\'e algebra as representations on a noncommutative spacetime with canonical commutation relations. These deformations are obtained by solving a set of conditions by an appropriate…

High Energy Physics - Theory · Physics 2009-11-10 Florian Koch , Efrossini Tsouchnika

Let $\Omega\subset \mathbb{R}^n$ be open and let $\mathcal{R}$ be a partial frame on $\Omega$, that is a set of $m$ linearly independent vector fields prescribed on $\Omega$ ($m\leq n$). We consider the issue of describing the set of all…

Differential Geometry · Mathematics 2017-09-25 Michael Benfield , Helge Kristian Jenssen , Irina A. Kogan

Finite-dimensional spaces which are invariant under the action of the Hamiltonian of the BC_N Inozemtsev model are introduced, and it is shown that higher commuting operators also preserve the finite-dimensional spaces. The relationship…

Quantum Algebra · Mathematics 2007-05-23 Kouichi Takemura

Fractional supersymmetric quantum mechanics of order $\lambda$ is realized in terms of the generators of a generalized deformed oscillator algebra and a Z$_{\lambda}$-grading structure is imposed on the Fock space of the latter. This…

Mathematical Physics · Physics 2008-11-26 C. Quesne

This paper is a continuation of our previous work \cite{wang2024complex}. It mainly deals with entire operators $T$ with deficiency index 1 \emph{systematically} from the complex-geometric viewpoint proposed in \cite{wang2024complex}. We…

Functional Analysis · Mathematics 2025-10-24 Yicao Wang

We introduce quasi-invariant polynomials for an arbitrary finite complex reflection group W. Unlike in the Coxeter case, the space Q_k of quasi-invariants of a given multiplicity is not, in general, an algebra but a module over the…

Representation Theory · Mathematics 2014-01-14 Yuri Berest , Oleg Chalykh

We prove that if the Schwarzian norm of a given complex-valued locally univalent harmonic mapping $f$ in the unit disk is small enough, then $f$ is, indeed, globally univalent and can be extended to a quasiconformal mapping in the extended…

Complex Variables · Mathematics 2014-10-21 Rodrigo Hernández , María J. Martín

q-Deformed harmonic oscillator algebra for real and root of unity values of the deformation parameter is discussed by using an extension of the number concept proposed by Gauss, namely the Q-numbers. A study of the reducibility of the Fock…

Quantum Algebra · Mathematics 2007-05-23 D. Galetti , J. T. Lunardi , B. M. Pimentel , M. Ruzzi
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