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Motivated by cognitive experiments providing evidence that large crossing-angles do not impair the readability of a graph drawing, RAC (Right Angle Crossing) drawings were introduced to address the problem of producing readable…

Computational Geometry · Computer Science 2022-07-01 Patrizio Angelini , Michael A. Bekos , Julia Katheder , Michael Kaufmann , Maximilian Pfister

In a right-angle crossing (RAC) drawing of a graph, each edge is represented as a polyline and edge crossings must occur at an angle of exactly $90^\circ$, where the number of bends on such polylines is typically restricted in some way.…

Computational Geometry · Computer Science 2023-08-24 Cornelius Brand , Robert Ganian , Sebastian Röder , Florian Schager

A RAC graph is one admitting a RAC drawing, that is, a polyline drawing in which each crossing occurs at a right angle. Originally motivated by psychological studies on readability of graph layouts, RAC graphs form one of the most prominent…

Data Structures and Algorithms · Computer Science 2023-06-30 Patrizio Angelini , Michael A. Bekos , Julia Katheder , Michael Kaufmann , Maximilian Pfister , Torsten Ueckerdt

A RAC-drawing of a graph is a straight-line drawing in which every crossing occurs at a right-angle. We show that deciding whether a graph has a RAC-drawing is as hard as the existential theory of the reals, even if we know that every edge…

Combinatorics · Mathematics 2021-07-28 Marcus Schaefer

In a RAC drawing of a graph, vertices are represented by points in the plane, adjacent vertices are connected by line segments, and crossings must form right angles. Graphs that admit such drawings are RAC graphs. RAC graphs are…

Computational Geometry · Computer Science 2020-07-10 Steven Chaplick , Henry Förster , Myroslav Kryven , Alexander Wolff

A graph is 1-planar if it has a drawing where each edge is crossed at most once. A drawing is RAC (Right Angle Crossing) if the edges cross only at right angles. The relationships between 1-planar graphs and RAC drawings have been partially…

Computational Geometry · Computer Science 2016-08-31 Walter Didimo , Giuseppe Liotta , Saeed Mehrabi , Fabrizio Montecchiani

Given two planar graphs that are defined on the same set of vertices, a RAC simultaneous drawing is one in which each graph is drawn planar, there are no edge overlaps and the crossings between the two graphs form right angles. The…

Computational Geometry · Computer Science 2016-11-23 Michael A. Bekos , Thomas C. van Dijk , Philipp Kindermann , Alexander Wolff

A k-bend right-angle-crossing drawing or (k-bend RAC drawing}, for short) of a graph is a polyline drawing where each edge has at most k bends and the angles formed at the crossing points of the edges are 90 degrees. Accordingly, a graph…

Data Structures and Algorithms · Computer Science 2018-09-03 Patrizio Angelini , Michael A. Bekos , Henry Förster , Michael Kaufmann

In this paper, we study tradeoffs between curve complexity and area of Right Angle Crossing drawings (RAC drawings), which is a challenging theoretical problem in graph drawing. Given a graph with $n$ vertices and $m$ edges, we provide a…

Computational Geometry · Computer Science 2020-01-10 Zahed Rahmati , Fatemeh Emami

In extension problems of partial graph drawings one is given an incomplete drawing of an input graph $G$ and is asked to complete the drawing while maintaining certain properties. A prominent area where such problems arise is that of…

Computational Geometry · Computer Science 2020-12-15 Robert Ganian , Thekla Hamm , Fabian Klute , Irene Parada , Birgit Vogtenhuber

A graph is near-planar if it can be obtained from a planar graph by adding an edge. We show the surprising fact that it is NP-hard to compute the crossing number of near-planar graphs. A graph is 1-planar if it has a drawing where every…

Computational Geometry · Computer Science 2012-03-28 Sergio Cabello , Bojan Mohar

We study the following classes of beyond-planar graphs: 1-planar, IC-planar, and NIC-planar graphs. These are the graphs that admit a 1-planar, IC-planar, and NIC-planar drawing, respectively. A drawing of a graph is 1-planar if every edge…

Computational Geometry · Computer Science 2019-08-12 Steven Chaplick , Fabian Lipp , Alexander Wolff , Johannes Zink

Point-set embeddings and large-angle crossings are two areas of graph drawing that independently have received a lot of attention in the past few years. In this paper, we consider problems in the intersection of these two areas. Given the…

Data Structures and Algorithms · Computer Science 2011-07-26 Martin Fink , Jan-Henrik Haunert , Tamara Mchedlidze , Joachim Spoerhase , Alexander Wolff

A graph G is an a-angle crossing (aAC) graph if every pair of crossing edges in G intersect at an angle of at least a. The concept of right angle crossing (RAC) graphs (a=Pi/2) was recently introduced by Didimo et. al. It was shown that any…

Data Structures and Algorithms · Computer Science 2013-03-12 Vida Dujmovic , Joachim Gudmundsson , Pat Morin , Thomas Wolle

An \emph{outer-RAC drawing} of a graph is a straight-line drawing where all vertices are incident to the outer cell and all edge crossings occur at a right angle. If additionally, all crossing edges are either horizontal or vertical, we…

Computational Complexity · Computer Science 2024-11-27 Förster , Julia Katheder , Giacomo Ortali

We study the problem of embedding graphs in the plane as good geometric spanners. That is, for a graph $G$, the goal is to construct a straight-line drawing $\Gamma$ of $G$ in the plane such that, for any two vertices $u$ and $v$ of $G$,…

Data Structures and Algorithms · Computer Science 2020-02-14 Oswin Aichholzer , Manuel Borrazzo , Prosenjit Bose , Jean Cardinal , Fabrizio Frati , Pat Morin , Birgit Vogtenhuber

A graph is NIC-planar if it admits a drawing in the plane with at most one crossing per edge and such that two pairs of crossing edges share at most one common end vertex. NIC-planarity generalizes IC-planarity, which allows a vertex to be…

Discrete Mathematics · Computer Science 2017-11-06 Christian Bachmaier , Franz J. Brandenburg , Kathrin Hanauer , Daniel Neuwirth , Josef Reislhuber

It is shown that every $n$-vertex graph that admits a 2-bend RAC drawing in the plane, where the edges are polylines with two bends per edge and any pair of edges can only cross at a right angle, has at most $20n-24$ edges for $n\geq 3$.…

Discrete Mathematics · Computer Science 2024-11-05 Csaba D. 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

Reeb graphs are simple topological descriptors with applications in many areas like topological data analysis and computational geometry. Despite their prevalence, visualization of Reeb graphs has received less attention. In this paper, we…

Computational Geometry · Computer Science 2025-05-20 Erin Chambers , Brittany Terese Fasy , Erfan Hosseini Sereshgi , Maarten Löffler
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