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We explore the interplay between different definitions of distortion for mappings $f\colon X\to \mathbb{R}^2$, where $X$ is any metric surface, meaning that $X$ is homeomorphic to a domain in $\mathbb{R}^2$ and has locally finite…

Metric Geometry · Mathematics 2024-05-14 Damaris Meier , Kai Rajala

We study the conformal dimension of fractal percolation and show that, almost surely, the conformal dimension of a fractal percolation is strictly smaller than its Hausdorff dimension.

Classical Analysis and ODEs · Mathematics 2020-04-17 Eino Rossi , Ville Suomala

In this paper, we obtain new bounds for the Hausdorff dimension of planar elliptic measure via the application of quasiconformal mappings, with these bounds depending solely on the ellipticity constant of the matrix. In fact, in our case…

Classical Analysis and ODEs · Mathematics 2025-11-04 Ignasi Guillén-Mola

Quasiconformal maps in the complex plane are homeomorphisms that satisfy certain geometric distortion inequalities; infinitesimally, they map circles to ellipses with bounded eccentricity. The local distortion properties of these maps give…

Complex Variables · Mathematics 2024-09-12 Rosemarie Bongers

We verify a conjecture of Rajala: if $(X,d)$ is a metric surface of locally finite Hausdorff 2-measure admitting some (geometrically) quasiconformal parametrization by a simply connected domain $\Omega \subset \mathbb{R}^2$, then there…

Metric Geometry · Mathematics 2021-12-20 Matthew Romney

In his celebrated paper on area distortion for quasiconformal mappings, Astala showed optimal area distortion bounds and dimension distortion estimates for planar quasiconformal mappings. He asked (Question 4.4) whether a finer result held,…

Complex Variables · Mathematics 2011-11-10 I. Uriarte-Tuero

We establish a uniformization result for metric surfaces - metric spaces that are topological surfaces with locally finite Hausdorff 2-measure. Using the geometric definition of quasiconformality, we show that a metric surface that can be…

Complex Variables · Mathematics 2019-09-20 Toni Ikonen

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

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 extend a well-known theorem by Jones and Makarov [JM] on the singularity of boundary distortion of planar conformal mappings. We use a different technique to recover the previous result and, moreover, generalize the result for…

Complex Variables · Mathematics 2008-02-19 Tomi Nieminen , Ignacio Uriarte-Tuero

In this article, we examine stretching and rotation of planar quasiconformal mappings on a line. We show that for almost every point on the line, the set of complex stretching exponents (describing stretching and rotation jointly) is…

Complex Variables · Mathematics 2021-10-28 Olli Hirviniemi , István Prause , Eero Saksman

We study piecewise quasiconformal covering maps of the unit circle. We provide sufficient conditions so that a conjugacy between two such dynamical systems has a quasiconformal or David extension to the unit disk. Our main result…

Dynamical Systems · Mathematics 2024-11-22 Yusheng Luo , Dimitrios Ntalampekos

In this paper we prove the sharp distortion estimates for the quasiconformal mappings in the plane, both in terms of the Riesz capacities from non linear potential theory and in terms of the Hausdorff measures.

Complex Variables · Mathematics 2010-02-05 K. Astala , A. Clop , X. Tolsa , I. Uriarte-Tuero , J. Verdera

We prove that the spacetime singular set of any suitable Leray-Hopf solution of the surface quasigeostrophic equation with fractional dissipation of order $0< \alpha < \frac{1}{2}$ has Hausdorff dimension at most $\frac{1}{2\alpha^2}\,.$…

Analysis of PDEs · Mathematics 2022-02-25 Maria Colombo , Silja Haffter

A quasiplane $f(V)$ is the image of an $n$-dimensional Euclidean subspace $V$ of ${\Bbb R}^N$ ($1\leq n\leq N-1$) under a quasiconformal map $f:{\Bbb R}^N\to{\Bbb R}^N$ . We give sufficient conditions in terms of the weak quasisymmetry…

Classical Analysis and ODEs · Mathematics 2015-07-01 Jonas Azzam , Matthew Badger , Tatiana Toro

We look for minimal conditions on a two-dimensional metric surface $X$ of locally finite Hausdorff $2$-measure under which $X$ admits an (almost) parametrization with good geometric and analytic properties. Only assuming that $X$ is locally…

Metric Geometry · Mathematics 2021-06-16 Damaris Meier , Stefan Wenger

The connections between quasi-Assouad dimension and tangents are studied. We apply these results to the calculation of the quasi-Assouad dimension for a class of planar self-affine sets. We also show that sets with decreasing gaps have…

Classical Analysis and ODEs · Mathematics 2019-06-27 Ignacio García , Kathryn Hare

We prove that for any $1 \le k<n$ and $s\le 1$, the union of any nonempty $s$-Hausdorff dimensional family of $k$-dimensional affine subspaces of ${\mathbb R}^n$ has Hausdorff dimension $k+s$. More generally, we show that for any $0 <…

Metric Geometry · Mathematics 2018-03-08 K. Héra , T. Keleti , A. Máthé

Sobolev mappings exhibiting only pointwise quasiregularity-type bounds have arisen in various applications, leading to a recently developed theory of quasiregular values. In this article, we show that by using rescaling, one obtains a…

Complex Variables · Mathematics 2024-05-03 Ilmari Kangasniemi , Jani Onninen

In this paper, we study the quasisymmetric Hausdorff minimality of homogeneous Moran sets. First, we obtain the Hausdorff dimension formula of two classes of homogeneous Moran sets which satisfy some conditions. Second, we show two special…

General Topology · Mathematics 2026-01-06 Jun Li , Yanzhe Li , Pingping Liu