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The classical Painlev\'e theorem tells that sets of zero length are removable for bounded analytic functions, while (some) sets of positive length are not. For general $K$-quasiregular mappings in planar domains the corresponding critical…

Complex Variables · Mathematics 2007-05-23 Kari Astala , Albert Clop , Joan Mateu , Joan Orobitg , Ignacio Uriarte-Tuero

In this paper, we consider mappings on uniform domains with exponentially integrable distortion whose Jacobian determinants are integrable. We show that such mappings can be extended to the boundary and moreover these extensions are…

Complex Variables · Mathematics 2024-10-15 Tuomo Akkinen , Chang-Yu Guo

We review a selection of the literature on the distortion of metric notions of dimension under quasiconformal, quasisymmetric, and Sobolev mappings. Our story begins with Gehring's landmark 1973 higher integrability theorem for…

Metric Geometry · Mathematics 2026-03-13 Jeremy T. Tyson

We prove a sharp result for the distortion of a hyperbolic type metric under $K$-quasiregular mappings of the upper half plane. The proof makes use of a new kind of Bernoulli inequality and the Schwarz lemma for quasiregular mappings.

Complex Variables · Mathematics 2025-03-14 Masayo Fujimura , Matti Vuorinen

We determine the extent to which certain classes of fractionally `smooth' continuous mappings between metric spaces distort various dimensions, including the Hausdorff, upper Minkowski (box-counting), and upper intermediate dimensions. Our…

Classical Analysis and ODEs · Mathematics 2025-10-16 Ryan Alvarado , Efstathios Konstantinos Chrontsios Garitsis

The manuscript is devoted to the boundary behavior of mappings with bounded and finite distortion, which has been actively studied recently. We consider mappings of domains of the Euclidean space that satisfy the inverse Poletsky inequality…

Complex Variables · Mathematics 2026-04-14 Victoria Desyatka , Evgeny Sevost'yanov

We establish uniformization results for metric spaces that are homeomorphic to the euclidean plane or sphere and have locally finite Hausdorff 2-measure. Applying the geometric definition of quasiconformality, we give a necessary and…

Complex Variables · Mathematics 2016-08-29 Kai Rajala

We prove that a harmonic quasiconformal mapping defined on a finitely connected domain in the plane, all of whose boundary components are either points or quasicircles, admits a quasiconformal extension to the whole plane if its Schwarzian…

Complex Variables · Mathematics 2021-02-05 Iason Efraimidis

Teichm\"uller's classical mapping problem for plane domains concerns finding a lower bound for the maximal dilatation of a quasiconformal homeomorphism which holds the boundary pointwise fixed, maps the domain onto itself, and maps a given…

Complex Variables · Mathematics 2013-04-15 Matti Vuorinen , Xiaohui Zhang

We study metric spaces defined via a conformal weight, or more generally a measurable Finsler structure, on a domain $\Omega \subset \mathbb{R}^2$ that vanishes on a compact set $E \subset \Omega$ and satisfies mild assumptions. Our main…

Metric Geometry · Mathematics 2020-06-08 Toni Ikonen , Matthew Romney

The article is devoted to the study of mappings that satisfy the so-called inverse Poletsky inequality. We consider mappings of quasiextremal distance domains, domains with a locally quasiconformal boundary, and domains which are regular in…

Complex Variables · Mathematics 2023-10-03 M. V. Androschuk , O. P. Dovhopiatyi , N. S. Ilkevych , E. A. Sevost'yanov

We prove a Koebe distortion theorem for the average derivative of a quasiconformal mapping between domains in the sub-Riemannian Heisenberg group $\mathbb{H}_1$. Several auxiliary properties of quasiconformal mappings between subdomains of…

Metric Geometry · Mathematics 2019-05-20 Tomasz Adamowicz , Katrin Fässler , Ben Warhurst

We prove that for mappings $W^{1,n}(B^n, \R^n),$ continuous up to the boundary, with modulus of continuity satisfying certain divergence condition, the image of the boundary of the unit ball has zero $n$-Hausdorff measure. For H\"older…

Classical Analysis and ODEs · Mathematics 2016-01-20 Aapo Kauranen , Pekka Koskela

We extend to all planar simply connected domains Makarov-type results about the Hausdorff dimension of $p$-harmonic measure pioneered by Lewis and Bennewitz in the context of quasidisks. The key to our analysis is a gradient estimate using…

Complex Variables · Mathematics 2009-02-03 John Lewis , Kaj Nyström , Pietro Poggi-Corradini

Optimal quasiconformal dimension distortions bounds for subsets of the complex plane have been established by Astala. We show that these estimates can be improved when one considers subsets of the real line of arbitrary Hausdorff dimension.…

Complex Variables · Mathematics 2024-02-05 Petteri Nissinen , István Prause

We construct a quasiconformal mapping of $n$-dimensional Euclidean space, $n \geq 2$, that simultaneously distorts the Hausdorff dimension of a nearly maximal collection of parallel lines by a given amount. This answers a question of…

Metric Geometry · Mathematics 2016-01-28 Zoltán M. Balogh , Jeremy T. Tyson , Kevin Wildrick

We prove a quantitative distortion theorem for iterated function systems that generate sets of continued fractions. As a consequence, we obtain upper and lower bounds on the Hausdorff dimension of any set of real or complex continued…

Number Theory · Mathematics 2020-02-25 Daniel Ingebretson

In this paper, we extend the celebrated global regularity theory of Naber-Valtorta [Ann. Math. 2017] to 1/2-harmonic mappings into manifolds. Inspired by their work, we first adapt Lin's defect measure theory [Ann. Math. 1999] to such maps…

Analysis of PDEs · Mathematics 2026-03-16 Changyu Guo , Guichun Jiang , Changyou Wang , Changlin Xiang , Gaofeng Zheng

We construct examples to show the sharpness of uniform continuity of quasiconformal mappings onto $s$-John domains. Our examples also give a negative answer to a prediction in [7].

Complex Variables · Mathematics 2024-10-15 Chang-Yu Guo , Pekka Koskela

We describe the variation of the Minkowski, packing and Hausdorff dimensions of a set moving under a holomorphic motion, as well as the variation of its area. Our method provides a new, unified approach to various celebrated theorems about…

Complex Variables · Mathematics 2023-04-10 Aidan Fuhrer , Thomas Ransford , Malik Younsi