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Related papers: Crossings and nesting in tangled-diagrams

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There has been significant research dedicated towards computing the crossing numbers of families of graphs resulting from the Cartesian products of small graphs with arbitrarily large paths, cycles and stars. For graphs with four or fewer…

Combinatorics · Mathematics 2021-06-08 Kieran Clancy , Michael Haythorpe , Alex Newcombe

A drawing of a graph is 1-planar if each edge participates in at most one crossing and adjacent edges do not cross. Up to symmetry, each crossing in a 1-planar drawing belongs to one out of six possible crossing types, where a type…

Data Structures and Algorithms · Computer Science 2025-11-20 Sergio Cabello , Alexander Dobler , Gašper Fijavž , Thekla Hamm , Mirko H. Wagner

A tripartite-circle drawing of a tripartite graph is a drawing in the plane, where each part of a vertex partition is placed on one of three disjoint circles, and the edges do not cross the circles. The tripartite-circle crossing number of…

Let $G$ be a multigraph with $n$ vertices and $e>4n$ edges, drawn in the plane such that any two parallel edges form a simple closed curve with at least one vertex in its interior and at least one vertex in its exterior. Pach and T\'oth (A…

Combinatorics · Mathematics 2021-10-20 Michael Kaufmann , Janos Pach , Geza Toth , Torsten Ueckerdt

Drawing a graph in the plane with as few crossings as possible is one of the central problems in graph drawing and computational geometry. Another option is to remove the smallest number of vertices or edges such that the remaining graph…

Computational Geometry · Computer Science 2024-04-16 Akanksha Agrawal , Sergio Cabello , Michael Kaufmann , Saket Saurabh , Roohani Sharma , Yushi Uno , Alexander Wolff

For a subclass of matchings, set partitions, and permutations, we describe a direct bijection involving only arc annotated diagrams that not only interchanges maximum nesting and crossing numbers, but also all refinements of crossing and…

Combinatorics · Mathematics 2012-10-23 Lily Yen

Determining whether there exists a graph such that its crossing number and pair crossing number are distinct is an important open problem in geometric graph theory. We show that $\textit{cr}(G)=O(\mathop{\mathrm{pcr}}(G)^{3/2})$ for every…

Combinatorics · Mathematics 2022-11-17 Oriol Solé Pi

Graph drawing beyond planarity focuses on drawings of high visual quality for non-planar graphs which are characterized by certain forbidden edge configurations. A natural criterion for the quality of a drawing is the number of edge…

Computational Geometry · Computer Science 2021-05-27 Nathan van Beusekom , Irene Parada , Bettina Speckmann

Any planar graph has a crossing-free straight-line drawing in the plane. A simultaneous geometric embedding of two n-vertex graphs is a straight-line drawing of both graphs on a common set of n points, such that the edges withing each…

Computational Geometry · Computer Science 2007-05-23 Martin Kutz

A weave is the lift to the Euclidean thickened plane of a set of infinitely many planar crossed geodesics, that can be characterized by a number of sets of threads describing the organization of the non-intersecting curves, together with a…

Geometric Topology · Mathematics 2022-02-04 Mizuki Fukuda , Motoko Kotani , Sonia Mahmoudi

For all $k \geq 1$, we show that deciding whether a graph is $k$-planar is NP-complete, extending the well-known fact that deciding 1-planarity is NP-complete. Furthermore, we show that the gap version of this decision problem is…

Combinatorics · Mathematics 2020-05-19 John C. Urschel , Jake Wellens

Given a surface with boundary and some points on its boundary, a polygon diagram is a way to connect those points as vertices of non-overlapping polygons on the surface. Such polygon diagrams represent non-crossing permutations on a surface…

Combinatorics · Mathematics 2019-09-27 Norman Do , Jian He , Daniel V. Mathews

A graph is called a $k$-planar unit distance graph if it can be drawn in the plane such that every edge is a unit line segment and is involved in at most $k$ crossings. We investigate $u_k(n)$, the maximum number of edges of such graphs on…

Combinatorics · Mathematics 2026-03-23 Panna Gehér , Dömötör Pálvölgyi , Dániel G. Simon , Géza Tóth

The crossing number of a graph is the minimum number of edge crossings that a graph can have when drawn in the plane. Determining this number, known as the Crossing Number problem, is a celebrated problem in combinatorial optimization. It…

Computational Geometry · Computer Science 2026-03-30 Petr Hliněný , Liana Khazaliya

We consider the task of drawing a graph on multiple horizontal layers, where each node is assigned a layer, and each edge connects nodes of different layers. Known algorithms determine the orders of nodes on each layer to minimize crossings…

Data Structures and Algorithms · Computer Science 2025-03-03 Alexander Dobler , Jakob Roithinger

A drawing of a graph in the plane is {\it pseudolinear} if the edges of the drawing can be extended to doubly-infinite curves that form an arrangement of pseudolines, that is, any pair of edges crosses precisely once. A special case are…

A tanglegram consists of two rooted binary trees and a perfect matching between their leaves, and a planar tanglegram is one that admits a layout with no crossings. We show that the problem of generating planar tanglegrams uniformly at…

Combinatorics · Mathematics 2023-04-13 Alexander E. Black , Kevin Liu , Alex Mcdonough , Garrett Nelson , Michael C. Wigal , Mei Yin , Youngho Yoo

Simple drawings are drawings of graphs in the plane or on the sphere such that vertices are distinct points, edges are Jordan arcs connecting their endpoints, and edges intersect at most once (either in a proper crossing or in a shared…

Computational Geometry · Computer Science 2022-08-12 Alfredo García , Javier Tejel , Birgit Vogtenhuber , Alexandra Weinberger

A {\em thrackle} is a graph drawn in the plane so that every pair of its edges meet exactly once: either at a common end vertex or in a proper crossing. We prove that any thrackle of $n$ vertices has at most $1.3984n$ edges. {\em…

Combinatorics · Mathematics 2017-08-29 Radoslav Fulek , János Pach

In this paper we present an algorithm that generates $k$-noncrossing, $\sigma$-modular diagrams with uniform probability. A diagram is a labeled graph of degree $\le 1$ over $n$ vertices drawn in a horizontal line with arcs $(i,j)$ in the…

Combinatorics · Mathematics 2010-06-16 Fenix W. D. Huang , Christian M. Reidys
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