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In 1994, Thomassen proved that every planar graph is 5-list-colorable. In 1995, Thomassen proved that every planar graph of girth at least five is 3-list-colorable. His proofs naturally lead to quadratic-time algorithms to find such…

Combinatorics · Mathematics 2019-11-07 Luke Postle

We present the first parallel fixed-parameter algorithm for subgraph isomorphism in planar graphs, bounded-genus graphs, and, more generally, all minor-closed graphs of locally bounded treewidth. Our randomized low depth algorithm has a…

Data Structures and Algorithms · Computer Science 2020-07-03 Lukas Gianinazzi , Torsten Hoefler

Recently, one has seen a surge of interest in developing such methods including ones for learning such representations for (undirected) graphs (while preserving important properties). However, most of the work to date on embedding graphs…

Social and Information Networks · Computer Science 2018-11-30 Jiankai Sun , Srinivasan Parthasarathy

In this paper, we analyze embeddings of grid graphs on orientable surfaces. We determine the genus of a large class of k-dimensional grid graphs and effective two-sided bounds for the genus of any 3-dimensional grid graph, both in terms of…

Combinatorics · Mathematics 2022-04-20 Christian Millichap , Fabian Salinas

We propose an algorithm to estimate the topology of an embedded metric graph from a well-sampled finite subset of the underlying graph.

Computational Geometry · Computer Science 2019-12-09 Brittany Terese Fasy , Rafal Komendarczyk , Sushovan Majhi , Carola Wenk

We investigate properties of sparse and tight surface graphs. In particular we derive topological inductive constructions for $(2, 2)$-tight surface graphs in the case of the sphere, the plane, the twice punctured sphere and the torus. In…

Combinatorics · Mathematics 2021-03-09 James Cruickshank , Derek Kitson , Stephen C. Power , Qays Shakir

It is well-known that every 3-connected planar graph has a unique planar embedding on the sphere. We study the extension to triangulated 1-planar graphs, T1P graphs for short, which admit an embedding in which each edge is crossed at most…

Discrete Mathematics · Computer Science 2023-12-27 Franz J. Brandenburg

The maximum number of vertices in a graph of maximum degree $\Delta\ge 3$ and fixed diameter $k\ge 2$ is upper bounded by $(1+o(1))(\Delta-1)^{k}$. If we restrict our graphs to certain classes, better upper bounds are known. For instance,…

Combinatorics · Mathematics 2015-12-14 Eran Nevo , Guillermo Pineda-Villavicencio , David R. Wood

A graph is called (generically) rigid in R^d if, for any choice of sufficiently generic edge lengths, it can be embedded in R^d in a finite number of distinct ways, modulo rigid transformations. Here, we deal with the problem of determining…

Computational Geometry · Computer Science 2014-10-24 Stylianos C. Despotakis , Ioannis Z. Emiris

The graph is one of the most widely used mathematical structures in engineering and science because of its representational power and inherent ability to demonstrate the relationship between objects. The objective of this work is to…

Data Structures and Algorithms · Computer Science 2021-01-01 Shri Prakash Dwivedi

Learning a graph topology to reveal the underlying relationship between data entities plays an important role in various machine learning and data analysis tasks. Under the assumption that structured data vary smoothly over a graph, the…

Machine Learning · Statistics 2023-08-23 Xingyue Pu , Tianyue Cao , Xiaoyun Zhang , Xiaowen Dong , Siheng Chen

The definition of $1$-planar graphs naturally extends graph planarity, namely a graph is $1$-planar if it can be drawn in the plane with at most one crossing per edge. Unfortunately, while testing graph planarity is solvable in linear time,…

Computational Geometry · Computer Science 2019-11-05 Carla Binucci , Walter Didimo , Fabrizio Montecchiani

In this article we describe an algorithm that can be applied for the generation of various classes of maps on orientable surfaces. It uses existing generators for abstract graphs and combines them with an efficient embedding and isomorphism…

Combinatorics · Mathematics 2024-08-30 Gunnar Brinkmann

Let $G$ be a planar $3$-graph (i.e., a planar graph with vertex degree at most three) with $n$ vertices. We present the first $O(n^2)$-time algorithm that computes a planar orthogonal drawing of $G$ with the minimum number of bends in the…

Data Structures and Algorithms · Computer Science 2018-09-06 Walter Didimo , Giuseppe Liotta , Maurizio Patrignani

A straight-line drawing $\delta$ of a planar graph $G$ need not be plane, but can be made so by \emph{untangling} it, that is, by moving some of the vertices of $G$. Let shift$(G,\delta)$ denote the minimum number of vertices that need to…

Computational Geometry · Computer Science 2009-01-27 Xavier Goaoc , Jan Kratochvil , Yoshio Okamoto , Chan-Su Shin , Andreas Spillner , Alexander Wolff

We study methods to manipulate weights in stress-graph embeddings to improve convex straight-line planar drawings of 3-connected planar graphs. Stress-graph embeddings are weighted versions of Tutte embeddings, where solving a linear system…

Computational Geometry · Computer Science 2023-09-01 Alvin Chiu , David Eppstein , Michael T. Goodrich

Graph isomorphism is an important computer science problem. The problem for the general case is unknown to be in polynomial time. The base algorithm for the general case works in quasi-polynomial time. The solutions in polynomial time for…

Discrete Mathematics · Computer Science 2017-11-23 Vaibhav Amit Patel

We consider the problem of computing the topology and describing the geometry of a parametric curve in $\mathbb{R}^n$. We present an algorithm, PTOPO, that constructs an abstract graph that is isotopic to the curve in the embedding space.…

Symbolic Computation · Computer Science 2022-02-18 Christina Katsamaki , Fabrice Rouillier , Elias Tsigaridas

This paper develops an algorithm that identifies and decomposes a median graph of a triangulation of a 2-dimensional (2D) oriented bordered surface and in addition restores all corresponding triangulation whenever they exist. The algorithm…

Combinatorics · Mathematics 2010-07-13 Weiwen Gu

We prove that every cyclically 4-edge-connected cubic graph that can be embedded in the torus, with the exceptional graph class called "Petersen-like", is 3-edge-colorable. This means every (non-trivial) toroidal snark can be obtained from…

Combinatorics · Mathematics 2025-05-13 Yuta Inoue , Ken-ichi Kawarabayashi , Atsuyuki Miyashita , Bojan Mohar , Tomohiro Sonobe