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Conformal Galilei algebra contains so(1,2) subalgebra which is the conformal algebra in one dimension. In this note we generalize methods previously developed for one-dimensional many-body systems and construct a unitary map relating a…

High Energy Physics - Theory · Physics 2008-11-26 A. V. Galajinsky

Consider the problem of finding a point in an ultrametric space with the minimum average distance to all points. We give this problem a Monte Carlo $O((\log^2(1/\epsilon))/\epsilon^3)$-time $(1+\epsilon)$-approximation algorithm for all…

Data Structures and Algorithms · Computer Science 2019-09-06 Ching-Lueh Chang

Given a set $S$ of $n$ points in the plane, we study the two-line-center problem: finding two lines that minimize the maximum distance from each point in $S$ to its closest line. We present a $(1+\varepsilon)$-approximation algorithm for…

Computational Geometry · Computer Science 2026-03-19 Chaeyoon Chung , Anil Maheshwari , Michiel Smid

We study quasiconformal mappings of the unit disk that have planar extension with controlled distortion. For these mappings we prove a bound for the modulus of continuity of the inverse map, which somewhat surprisingly is almost as good as…

Complex Variables · Mathematics 2021-10-04 Olli Hirviniemi , Lauri Hitruhin , István Prause , Eero Saksman

Calculating the diameter of an undirected graph requires quadratic running time under the Strong Exponential Time Hypothesis and this barrier works even against any approximation better than 3/2. For planar graphs with positive edge…

Data Structures and Algorithms · Computer Science 2025-07-08 Michał Włodarczyk

Let $P$ be a set of $n$ points in the plane. We show how to find, for a given integer $k>0$, the smallest-area axis-parallel rectangle that covers $k$ points of $P$ in $O(nk^2 \log n+ n\log^2 n)$ time. We also consider the problem of, given…

Computational Geometry · Computer Science 2019-07-12 Mark de Berg , Sergio Cabello , Otfried Cheong , David Eppstein , Christian Knauer

We present a $(1- \varepsilon)$-approximation algorithms for maximum cardinality matchings in disk intersection graphs -- all with near linear running time. We also present estimation algorithm that returns $(1\pm…

Computational Geometry · Computer Science 2022-03-17 Sariel Har-Peled , Everett Yang

In this paper, we provide new discrete uniformization theorems for bounded, $m$-connected planar domains. To this end, we consider a planar, bounded, $m$-connected domain $\Omega$ and let $\bord\Omega$ be its boundary. Let $\mathcal{T}$…

Geometric Topology · Mathematics 2013-12-24 Sa'ar Hersonsky

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 present new data structures for approximately counting the number of points in orthogonal range. There is a deterministic linear space data structure that supports updates in O(1) time and approximates the number of elements in a 1-D…

Data Structures and Algorithms · Computer Science 2009-10-05 Yakov Nekrich

We prove that a conformal mapping defined on the unit disk belongs to a weighted Bergman space if and only if certain integrals involving the harmonic measure converge. With the aid of this theorem, we give a geometric characterization of…

Complex Variables · Mathematics 2021-09-23 Christina Karafyllia , Nikolaos Karamanlis

Unbreakable decomposition, introduced by Cygan et al. (SICOMP'19) and Cygan et al. (TALG'20), has proven to be one of the most powerful tools for parameterized graph cut problems in recent years. Unfortunately, all known constructions…

Data Structures and Algorithms · Computer Science 2024-08-20 Aditya Anand , Euiwoong Lee , Jason Li , Yaowei Long , Thatchaphol Saranurak

An $\epsilon$-distance-uniform graph is one in which from every vertex, all but an $\epsilon$-fraction of the remaining vertices are at some fixed distance $d$, called the critical distance. We consider the maximum possible value of $d$ in…

Combinatorics · Mathematics 2017-08-18 Mikhail Lavrov , Po-Shen Loh , Arnau Messegué

IC-planar graphs are those graphs that admit a drawing where no two crossed edges share an end-vertex and each edge is crossed at most once. They are a proper subfamily of the 1-planar graphs. Given an embedded IC-planar graph $G$ with $n$…

Computational Geometry · Computer Science 2016-07-19 Franz J. Brandenburg , Walter Didimo , William S. Evans , Philipp Kindermann , Giuseppe Liotta , Fabrizio Montecchiani

The conformal deformations are contained in two classes of mappings: quasiconformal and harmonic mappings. In this paper we consider the intersection of these classes. We show that, every $K$ quasiconformal harmonic mapping between…

Analysis of PDEs · Mathematics 2011-03-09 David Kalaj

Conformal mapping of a slab of a two-dimensional ultrasonic crystal generate a closed geometrical arrangement of ultrasonic scatterers with appealing acoustic properties. This acoustic shell is able to confine ultrasonic modes. Some of…

Fluid Dynamics · Physics 2021-11-05 A. Bazan , M. Torres , F. R. Montero de Espinosa , R. Quintero-Torres , J. L. Aragon

A classic result of Brooks, Smith, Stone and Tutte associates to any finite planar network with distinguished source and sink vertices, a tiling of a rectangle by smaller subrectangles whose aspect ratios are given by the conductances of…

Complex Variables · Mathematics 2025-05-22 Ilia Binder , David Pechersky

This note examines sufficient conditions for the quasiconformal extendibility of harmonic mappings defined in the unit disk. It is demonstrated that a harmonic strongly starlike mapping admits a quasiconformal extension to the entire plane,…

Complex Variables · Mathematics 2025-09-03 Xiu-Shuang Ma

Local conformal symmetry is usually considered to be an approximate symmetry of nature, which is explicitly and badly broken. Arguments are brought forward here why it has to be turned into an exact symmetry that is spontaneously broken. As…

General Relativity and Quantum Cosmology · Physics 2015-03-18 Gerard T. Hooft

We consider approximate distance oracles for edge-weighted n-vertex undirected planar graphs. Given fixed epsilon > 0, we present a (1+epsilon)-approximate distance oracle with O(n(loglog n)^2) space and O((loglog n)^3) query time. This…

Data Structures and Algorithms · Computer Science 2016-01-06 Christian Wulff-Nilsen