Univalent Harmonic Mappings of Annuli
Univalent mappings of the plane into itself
Univalent -harmonic mappings : applications to composites
This paper is part of a larger project initiated with [2]. The final aim of the present paper is to give bounds for the homogenized (or effective) conductivity in two dimensional linear conductivity. The main focus is therefore the periodic setting. We prove new variational principles that are shown to be of interest in finding bounds on the homogenized conductivity. Our results unify previous approaches by the second author and make transparent the central role of quasiconformal mappings in all...
Univalent σ-harmonic mappings: applications to composites
This paper is part of a larger project initiated with [2]. The final aim of the present paper is to give bounds for the homogenized (or effective) conductivity in two dimensional linear conductivity. The main focus is therefore the periodic setting. We prove new variational principles that are shown to be of interest in finding bounds on the homogenized conductivity. Our results unify previous approaches by the second author and make transparent the central role of quasiconformal mappings in all...
Universal Covering Maps for Variable Regions.
Universal Teichmüller space and Fourier series.
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Unrectifiable 1-sets have vanishing analytic capacity.
We complete the proof of a conjecture of Vitushkin that says that if E is a compact set in the complex plane with finite 1-dimensional Hausdorff measure, then E has vanishing analytic capacity (i.e., all bounded anlytic functions on the complement of E are constant) if and only if E is purely unrectifiable (i.e., the intersection of E with any curve of finite length has zero 1-dimensional Hausdorff measure). As in a previous paper with P. Mattila, the proof relies on a rectifiability criterion using...
Upper bounds for the norm of Fekete polynomials on subarcs
Upper sets and quasisymmetric maps.
Use of logarithmic sums to estimate polynomials.
Use of the Power inequality in connection of coefficient regions for bounded univalent functions
Valence and oscillation of functions in the unit disk.
Variability regions of close-to-convex functions
M. Biernacki gave in 1936 concrete forms of the variability regions of z/f(z) and zf'(z)/f(z) of close-to-convex functions f for a fixed z with |z|<1. The forms are, however, not necessarily convenient to determine the shape of the full variability region of zf'(z)/f(z) over all close-to-convex functions f and all points z with |z|<1. We propose a couple of other forms of the variability regions and see that the full variability region of zf'(z)/f(z) is indeed the complex plane minus the origin....
Variability sets on Riemann surfaces and forgetful maps between Teichmüller spaces.
Varianten des Schwarzschen Lemma.
Variation of quasiconformal mappings on lines
We obtain improved regularity of homeomorphic solutions of the reduced Beltrami equation, as compared to the standard Beltrami equation. Such an improvement is not possible in terms of Hölder or Sobolev regularity; instead, our results concern the generalized variation of restrictions to lines. Specifically, we prove that the restriction to any line segment has finite p-variation for all p > 1 but not necessarily for p = 1.
Variations of Robin capacity and applications.
Vector fields on the space of functions univalent inside the unit disk via Faber polynomials.
Velocity induced by a plane uniform vortex having the Schwarz function of its boundary with two simple poles.