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One of the landmarks in approximation algorithms is the $O(\sqrt{\log n})$-approximation algorithm for the Uniform Sparsest Cut problem by Arora, Rao and Vazirani from 2004. The algorithm is based on a semidefinite program that finds an…

Data Structures and Algorithms · Computer Science 2016-07-05 Thomas Rothvoss

We prove the first nontrivial worst-case lower bounds for two closely related problems. First, $\Omega(n^{3/2})$ degree-1 reductions, series-parallel reductions, and $\Delta$Y transformations are required in the worst case to reduce an…

Computational Geometry · Computer Science 2015-10-05 Hsien-Chih Chang , Jeff Erickson

We first show that the union of a projective curve with one of its extremal secant lines satisfies the linear general position principle for hyperplane sections. We use this to give an improved approximation of the Betti numbers of curves…

Algebraic Geometry · Mathematics 2009-05-29 Markus Brodmann , Peter Schenzel

In many singular metric spaces, the regularity of a shortest-length curve is unknown. Algebraic varieties, or more generally sets defined by finitely many polynomial or real analytic equalities or inequalities, all locally partition into…

Differential Geometry · Mathematics 2023-01-30 Chengcheng Yang

Let $\mathbb{K}$ be an algebraically closed field. In this paper, we consider the class of smooth plane curves of degree $n+1>3$ over $\mathbb{K}$, containing three points, $P_1,P_2,$ and $P_3$, such that $nP_1+P_2$, $nP_2+P_3$, and…

Number Theory · Mathematics 2021-07-20 Herivelto Borges , Gregory Duran

We are interested in shapes of real algebraic curves in the plane and regions surrounded by them: they are named refined algebraic domains by the author. As characteristic finite sets, we consider points contained in two curves and the sets…

Algebraic Geometry · Mathematics 2025-04-08 Naoki Kitazawa

We establish an improved upper bound for the number of incidences between m points and n circles in three dimensions. The previous best known bound, originally established for the planar case and later extended to any dimension $\ge 2$, is…

Combinatorics · Mathematics 2019-02-20 Micha Sharir , Adam Sheffer , Joshua Zahl

It is known for a long time that a nonsingular real algebraic curve of degree 2k in the projective plane cannot have more than 7/2*k^2-9/4*k+3/2$ even ovals. We show here that this upper bound is asymptotically sharp, that is to say we…

Algebraic Geometry · Mathematics 2007-05-23 Erwan brugalle

We introduce the separating semigroup of a real algebraic curve of dividing type. The elements of this semigroup record the possible degrees of the covering maps obtained by restricting separating morphisms to the real part of the curve. We…

Algebraic Geometry · Mathematics 2020-08-04 Mario Kummer , Kristin Shaw

A notion of dual curve for pseudoholomorphic curves in 4--manifolds turns out to be possible only if the notion of almost complex structure structure is slightly generalized. The resulting structure is as easy (perhaps easier) to work with,…

Differential Geometry · Mathematics 2007-05-23 Benjamin McKay

We prove new bounds on the number of incidences between points and higher degree algebraic curves. The key ingredient is an improved initial bound, which is valid for all fields. Then we apply the polynomial method to obtain global bounds…

Combinatorics · Mathematics 2015-03-31 Hong Wang , Ben Yang , Ruixiang Zhang

In [5], without giving a detailed proof, Yamauchi provided a formula to calculate the genus of a certain family of smooth complete intersection algebraic curves. That formula is used extensively in [1] to study the algebraic curves for…

Algebraic Geometry · Mathematics 2019-10-08 Sajad Salami

Arrangements of lines and pseudolines are fundamental objects in discrete and computational geometry. They also appear in other areas of computer science, such as the study of sorting networks. Let $B_n$ be the number of nonisomorphic…

Combinatorics · Mathematics 2018-12-10 Adrian Dumitrescu , Ritankar Mandal

Let $\Gamma$ be an arrangement of Jordan curves in the plane, i.e., simple closed curves in the plane. For any curve $\gamma \in \Gamma$, we denote the bounded region enclosed by $\gamma$ as $\tilde{\gamma}$. We say that $\Gamma$ is…

Computational Geometry · Computer Science 2026-02-19 Suryendu Dalal , Rahul Gangopadhyay , Rajiv Raman , Saurabh Ray

In this paper we present a novel non-parametric method of simplifying piecewise linear curves and we apply this method as a statistical approximation of structure within sequential data in the plane. We consider the problem of minimizing…

Computational Geometry · Computer Science 2012-05-31 Stephane Durocher , Alexandre Leblanc , Jason Morrison , Matthew Skala

The Zariski closure of the central path which interior point algorithms track in convex optimization problems such as linear, quadratic, and semidefinite programs is an algebraic curve. The degree of this curve has been studied in relation…

Optimization and Control · Mathematics 2021-04-19 Serkan Hoşten , Isabelle Shankar , Angélica Torres

In this paper we establish an improved bound for the number of incidences between a set $P$ of $m$ points and a set $H$ of $n$ planes in $\mathbb R^3$, provided that the points lie on a two-dimensional nonlinear irreducible algebraic…

Combinatorics · Mathematics 2017-05-31 Micha Sharir , Noam Solomon

We prove an incidence theorem for points and curves in the complex plane. Given a set of $m$ points in ${\mathbb R}^2$ and a set of $n$ curves with $k$ degrees of freedom, Pach and Sharir proved that the number of point-curve incidences is…

Combinatorics · Mathematics 2018-07-18 Adam Sheffer , Endre Szabó , Joshua Zahl

In this work, we use algebraic methods for studying distance computation and subgraph detection tasks in the congested clique model. Specifically, we adapt parallel matrix multiplication implementations to the congested clique, obtaining an…

Distributed, Parallel, and Cluster Computing · Computer Science 2019-12-24 Keren Censor-Hillel , Petteri Kaski , Janne H. Korhonen , Christoph Lenzen , Ami Paz , Jukka Suomela

We show that the maximum number of pairwise non-overlapping $k$-rich lenses (lenses formed by at least $k$ circles) in an arrangement of $n$ circles in the plane is $O\left(\frac{n^{3/2}\log{(n/k^3)}}{k^{5/2}} + \frac{n}{k} \right)$, and…

Combinatorics · Mathematics 2020-12-09 Esther Ezra , Orit E. Raz , Micha Sharir , Joshua Zahl