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We prove that if a continuous piecewise-smooth map on $\mathbb{R}^n$ is comprised of two linear functions, has a bounded orbit, and satisfies a certain non-degeneracy condition, then it has a fixed point. The result has important…

Dynamical Systems · Mathematics 2024-12-17 David J. W. Simpson

In this paper, we present several necessary and sufficient conditions for a harmonic mapping to be normal. Also, we discuss maximum principle and five-point theorem for normal harmonic mappings. Furthermore, we investigate the convergence…

Complex Variables · Mathematics 2020-09-01 Hua Deng , Saminathan Ponnusamy , Jinjing Qiao

We prove a theorem on distortion of cross ratio of four points under the mapping effected by a complex polynomial with restricted critical values. Its corollaries include inequalities involving the absolute value and certain coefficients of…

Complex Variables · Mathematics 2013-01-18 V. N. Dubinin

The sharp growth and distortion theorems are established for slice monogenic extensions of univalent functions on the unit disc $\mathbb D\subset \mathbb C$ in the setting of Clifford algebras, based on a new convex combination identity.…

Complex Variables · Mathematics 2017-01-17 Guangbin Ren , Xieping Wang

We present a family of sense-preserving harmonic mappings in the unit disk related to the classical generalized (analytic) Koebe functions. We prove that these are precisely the mappings that maximize simultaneously the real part of every…

Complex Variables · Mathematics 2015-11-03 Álvaro Ferrada-Salas , María J. Martín

In this paper, we establish three new versions of Landau-type theorems for bounded bi-analytic functions of the form $F(z)=\bar{z}G(z)+H(z)$, where $G$ and $H$ are analytic in the unit disk $|z|<1$ with $G(0)=H(0)=0$ and $H'(0)=1$. In…

Complex Variables · Mathematics 2023-02-16 Ming-Sheng Liu , Saminathan Ponnusamy

In this paper, we address several interconnected problems in the theory of harmonic maps between Riemannian manifolds. First, we present necessary background and establish one of the main results of the paper: a criterion characterizing…

Differential Geometry · Mathematics 2025-07-14 Sergey Stepanov , Irina Tsyganok

We determine the representation theorem, distortion theorem, coefficients estimate and Bohr's radius for log-harmonic starlike mappings of order $\alpha$, which are generalization of some earlier results. In addition, the inner mapping…

Complex Variables · Mathematics 2018-08-23 ZhiHong Liu , Saminathan Ponnusamy

We consider the problem of computing the distance-dependent two-point function of general planar maps and hypermaps, i.e. the problem of counting such maps with two marked points at a prescribed distance. The maps considered here may have…

Combinatorics · Mathematics 2015-07-21 Jérémie Bouttier , Éric Fusy , Emmanuel Guitter

We establish a finite-dimensional version of the Arveson-Stinespring dilation theorem for unital completely positive maps on operator systems. This result can be seen as a general principle to deduce finite-dimensional dilation theorems…

Functional Analysis · Mathematics 2022-04-25 Michael Hartz , Martino Lupini

The hereditary property of convexity and starlikeness for conformal mappings does not generalize to univalent harmonic mappings. This failure leads us to the notion of fully starlike and convex mappings of order \alpha, (0\leq \alpha<1). A…

Complex Variables · Mathematics 2012-07-18 Sumit Nagpal , V. Ravichandran

As an application of Brouwer's fixed-point theorem we prove that a continuously differentiable convex function with gradient of constant norm is an affine mapping. It is a first-order characterization of affine mappings among continuously…

Classical Analysis and ODEs · Mathematics 2025-11-10 Csaba Vincze

In this paper, we study the existence of fixed points for mappings defined on complete (compact) metric space (X, d) satisfying a general contractive (contraction) inequality depended on another function. These conditions are analogous to…

Functional Analysis · Mathematics 2009-03-10 A. Beiranvand , S. Moradi , M. Omid , H. Pazandeh

For a disk $D$ in the plane $\mathbb R^2$ and a plane map $f$, we give several conditions on the restriction of $f$ to the boundary $\partial D$ of $D$ which imply the existence of a fixed point of $f$ in some specified domain in $D$. These…

Dynamical Systems · Mathematics 2024-02-27 Jiehua Mai , Enhui Shi , Kesong Yan , Fanping Zeng

Polyharmonic maps of order k (briefly, k-harmonic maps) are a natural generalization of harmonic and biharmonic maps. These maps are defined as the critical points of suitable higher order functionals which extend the classical energy…

Differential Geometry · Mathematics 2025-01-10 Volker Branding , Stefano Montaldo , Cezar Oniciuc , Andrea Ratto

We consider harmonic maps on simply connected Riemann surfaces into the group $\mathrm{U}(n)$ of unitary matrices of order $n$. It is known that a harmonic map with an associated algebraic extended solution can be deformed into a new…

Functional Analysis · Mathematics 2017-02-22 Alexandru Aleman , María J. Martín , Anna-Maria Persson , Martin Svensson

The main aim of this paper is to obtain the sharp upper and lower bounds for the growth and distortion of the analytic part $h$ of sense-preserving convex $K$-quasiconformal harmonic mappings.

Complex Variables · Mathematics 2025-05-26 Peijin Li , Saminathan Ponnusamy

The purpose of this paper is to present some multidimensional fixed-point theorems and their applications. For this, we provide a multidimensional fixed point theorem and then using this theorem we prove the existence and uniqueness of a…

Functional Analysis · Mathematics 2021-07-28 H. Akhadkulov , S. Akhatkulov , T. Y. Ying , R. Tilavov

In this paper, we extend the uniqueness theorem for meromorphic mappings to the case where the family of hyperplanes depends on the meromorphic mapping and where the meromorphic mappings may be degenerate.

Complex Variables · Mathematics 2014-12-01 G. Dethloff , Tan Tran Van , Si Duc Quang

Invertible compositions of one-dimensional maps are studied which are assumed to include maps with non-positive Schwarzian derivative and others whose sum of distortions is bounded. If the assumptions of the Koebe principle hold, we show…

Dynamical Systems · Mathematics 2016-09-06 Grzegorz Swiatek