Harmonic mappings in the exterior of the unit disk

Magdalena Gregorczyk; Jarosław Widomski

Displaying similar documents to “Harmonic mappings in the exterior of the unit disk”

Harmonic mappings in the exterior of the unit disk

Jarosław Widomski, Magdalena Gregorczyk (2010)

Annales UMCS, Mathematica

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In this paper we consider a class of univalent orientation-preserving harmonic functions defined on the exterior of the unit disk which satisfy the condition [...] . We are interested in finding radius of univalence and convexity for such class and we find extremal functions. Convolution, convex combination, and explicit quasiconformal extension for this class are also determined.

Convolutions of harmonic right half-plane mappings

YingChun Li, ZhiHong Liu (2016)

Open Mathematics

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We first prove that the convolution of a normalized right half-plane mapping with another subclass of normalized right half-plane mappings with the dilatation [...] −z(a+z)/(1+az) $- z (a + z) / (1 + a z)$ is CHD (convex in the horizontal direction) provided [...] a=1 $a = 1$ or [...] −1≤a≤0 $- 1 \leq a \leq 0$ . Secondly, we give a simply method to prove the convolution of two special subclasses of harmonic univalent mappings in the right half-plane is CHD which was proved by Kumar et al. [1, Theorem 2.2]. In addition, we derive...

Univalent harmonic mappings II

Albert E. Livingston (1997)

Annales Polonici Mathematici

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Let a < 0 < b and Ω(a,b) = ℂ - ((-∞, a] ∪ [b,+∞)) and U= z: |z| < 1. We consider the class $S_{H} (U, Ω (a, b))$ of functions f which are univalent, harmonic and sense-preserving with f(U) = Ω and satisfying f(0) = 0, $f_{z} (0) > 0$ and $f_{z} ̅ (0) = 0$ .

On the order of starlikeness and convexity of complex harmonic functions with a two-parameter coefficient condition

Agnieszka Sibelska (2010)

Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica

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The article of J. Clunie and T. Sheil-Small [3], published in 1984, intensified the investigations of complex functions harmonic in the unit disc $Δ$ . In particular, many papers about some classes of complex mappings with the coefficient conditions have been published. Consideration of this type was undertaken in the period 1998–2004 by Y. Avci and E. Złotkiewicz [2], A. Ganczar [5], Z. J. Jakubowski, G. Adamczyk, A. Łazinska and A. Sibelska [1], [8], [7], H. Silverman [12] and J. M. Jahangiri...

Quasihomographies in the theory of Teichmüller spaces

Zając Józef

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CONTENTSIntroduction............................................................................................................................5 I. Special functions of quasiconformal theory.....................................................................10 1. Introduction.................................................................................................................10 2. The distortion function $Φ_{K}$ .....................................................................................11 3....

The generalized Neumann-Poincaré operator and its spectrum

Partyka Dariusz

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CONTENTSIntroduction..........................................................................................................................................................................5Preliminaries. Complex harmonic functions..........................................................................................................................7I. Spectral values and eigenvalues of a Jordan curve........................................................................................................19 1.1....

Loewner chains and quasiconformal extension of holomorphic mappings

Hidetaka Hamada, Gabriela Kohr (2003)

Annales Polonici Mathematici

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Let f(z,t) be a Loewner chain on the Euclidean unit ball B in ℂⁿ. Assume that f(z) = f(z,0) is quasiconformal. We give a sufficient condition for f to extend to a quasiconformal homeomorphism of $ℝ^{2 n}$ onto itself.

Uniform convergence of the generalized Bieberbach polynomials in regions with zero angles

F. G. Abdullayev (2001)

Czechoslovak Mathematical Journal

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Let $C$ be the extended complex plane; $G \subset C$ a finite Jordan with $0 \in G$ ; $w = ϕ (z)$ the conformal mapping of $G$ onto the disk $B (0; ρ_{0}) : = \}w |w| < ρ_{0}\{$ normalized by $ϕ (0) = 0$ and $ϕ^{'} (0) = 1$ . Let us set $ϕ_{p} (z) : = \int_{0}^{z} {[ϕ^{'} (ζ)]}^{2 / p} d ζ$ , and let $π_{n, p} (z)$ be the generalized Bieberbach polynomial of degree $n$ for the pair $(G, 0)$ , which minimizes the integral $\underset{G}{\int \int} {|ϕ_{p}^{'} (z) - P_{n}^{'} (z)|}^{p} d σ_{z}$ in the class of all polynomials of degree not exceeding $\leq n$ with $P_{n} (0) = 0$ , $P_{n}^{'} (0) = 1$ . In this paper we study the uniform convergence of the generalized Bieberbach polynomials $π_{n, p} (z)$ to $ϕ_{p} (z)$ on $\bar{G}$ with interior and exterior zero angles and determine its dependence...

Regularity theorems for solutions of partial differential equations for quasiconformal mappings in several dimensions

Tadeusz Iwaniec

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CONTENTSPreliminaries........................................................................................................ 51. Auxiliary results......................................................................................................... 132. The second order equations.................................................................................. 143. Some properties of Sobolev and Besov spaces................................................ 204. Classes $Λ^{α} (G, H)$ , 0 < a...

Landau's theorem for p-harmonic mappings in several variables

Sh. Chen, S. Ponnusamy, X. Wang (2012)

Annales Polonici Mathematici

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A 2p-times continuously differentiable complex-valued function f = u + iv in a domain D ⊆ ℂ is p-harmonic if f satisfies the p-harmonic equation $Δ^{p} f = 0$ , where p (≥ 1) is a positive integer and Δ represents the complex Laplacian operator. If Ω ⊂ ℂⁿ is a domain, then a function $f : Ω \to ℂ^{m}$ is said to be p-harmonic in Ω if each component function $f_{i}$ (i∈ 1,...,m) of $f = (f ₁, . . ., f_{m})$ is p-harmonic with respect to each variable separately. In this paper, we prove Landau and Bloch’s theorem for a class of p-harmonic mappings...

Coefficient inequalities for concave and meromorphically starlike univalent functions

B. Bhowmik, S. Ponnusamy (2008)

Annales Polonici Mathematici

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Let denote the open unit disk and f: → ℂ̅ be meromorphic and univalent in with a simple pole at p ∈ (0,1) and satisfying the standard normalization f(0) = f’(0)-1 = 0. Also, assume that f has the expansion $f (z) = \sum_{n = - 1}^{\infty} a ₙ (z - p) ⁿ$ , |z-p| < 1-p, and maps onto a domain whose complement with respect to ℂ̅ is a convex set (starlike set with respect to a point w₀ ∈ ℂ, w₀ ≠ 0 resp.). We call such functions concave (meromorphically starlike resp.) univalent functions and denote this class by $C o (p) (Σ^{s} (p, w ₀)$ resp.). We prove...

A critical growth rate for harmonic and subharmonic functions in the open ball in $R^{n}$

Krzysztof Samotij (1987)

Colloquium Mathematicae

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Quasiconformal mappings and exponentially integrable functions

Fernando Farroni, Raffaella Giova (2011)

Studia Mathematica

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We prove that a K-quasiconformal mapping f:ℝ² → ℝ² which maps the unit disk onto itself preserves the space EXP() of exponentially integrable functions over , in the sense that u ∈ EXP() if and only if $u \circ f^{- 1} \in E X P ()$ . Moreover, if f is assumed to be conformal outside the unit disk and principal, we provide the estimate $1 / (1 + K l o g K) \leq (| | u \circ f^{- 1} {| |}_{E X P ()} {) / (| | u | |}_{E X P ()}) \leq 1 + K l o g K$ for every u ∈ EXP(). Similarly, we consider the distance from $L^{\infty}$ in EXP and we prove that if f: Ω → Ω’ is a K-quasiconformal mapping and G ⊂ ⊂ Ω, then $1 / K \leq (d i s t_{E X P (f (G))} (u \circ f^{- 1}, L^{\infty} (f (G)))) / (d i s t_{E X P (f (G))} (u, L^{\infty} (G))) \leq K$ for every u ∈ EXP(). We also...

A class of functions containing polyharmonic functions in ℝⁿ

V. Anandam, M. Damlakhi (2003)

Annales Polonici Mathematici

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Some properties of the functions of the form $v (x) = \sum_{i = 0}^{m} {| x |}^{i} h_{i} (x)$ in ℝⁿ, n ≥ 2, where each $h_{i}$ is a harmonic function defined outside a compact set, are obtained using the harmonic measures.

Complex Ginzburg-Landau equations in high dimensions and codimension two area minimizing currents

Fanghua Lin, Tristan Rivière (1999)

Journal of the European Mathematical Society

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There is an obvious topological obstruction for a finite energy unimodular harmonic extension of a $S^{1}$ -valued function defined on the boundary of a bounded regular domain of $R^{n}$ . When such extensions do not exist, we use the Ginzburg-Landau relaxation procedure. We prove that, up to a subsequence, a sequence of Ginzburg-Landau minimizers, as the coupling parameter tends to infinity, converges to a unimodular harmonic map away from a codimension-2 minimal current minimizing the area within...

A proof of the Livingston conjecture for the fourth and the fifth coefficient of concave univalent functions

Karl-Joachim Wirths (2004)

Annales Polonici Mathematici

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Let D denote the open unit disc and f:D → ℂ̅ be meromorphic and injective in D. We further assume that f has a simple pole at the point p ∈ (0,1) and an expansion $f (z) = z + \sum_{n = 2}^{\infty} a ₙ (f) z ⁿ$ , |z| < p. In particular, we consider f that map D onto a domain whose complement with respect to ℂ̅ is convex. Because of the shape of f(D) these functions will be called concave univalent functions with pole p and the family of these functions is denoted by Co(p). It is proved that for p ∈ (0,1) the domain of variability...

On separately subharmonic functions (Lelong’s problem)

A. Sadullaev (2011)

Annales de la faculté des sciences de Toulouse Mathématiques

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The main result of the present paper is : every separately-subharmonic function $u (x, y)$ , which is harmonic in $y$ , can be represented locally as a sum two functions, $u = u^{*} + U$ , where $U$ is subharmonic and $u^{*}$ is harmonic in $y$ , subharmonic in $x$ and harmonic in $(x, y)$ outside of some nowhere dense set $S$ .

Dirichlet's principle, distortion and related problems for harmonic mappings.

Mateljević, Miodrag (2004)

Publications de l'Institut Mathématique. Nouvelle Série

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On harmonic quasiconformal quasi-isometries.

Mateljević, M., Vuorinen, M. (2010)

Journal of Inequalities and Applications [electronic only]

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On Polynomially Bounded Harmonic Functions on the $Z^{d}$ Lattice

Piotr Nayar (2009)

Bulletin of the Polish Academy of Sciences. Mathematics

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We prove that if $f : Z^{d} \to R$ is harmonic and there exists a polynomial $W : Z^{d} \to R$ such that f + W is nonnegative, then f is a polynomial.