Results 1 to 10 of about 28,792 (119)

The structure and the list 3-dynamic coloring of outer-1-planar graphs [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2021
An outer-1-planar graph is a graph admitting a drawing in the plane so that all vertices appear in the outer region of the drawing and every edge crosses at most one other edge.
Yan Li, Xin Zhang
doaj   +1 more source

Improved product structure for graphs on surfaces [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2022
Dujmovi\'c, Joret, Micek, Morin, Ueckerdt and Wood [J. ACM 2020] proved that for every graph $G$ with Euler genus $g$ there is a graph $H$ with treewidth at most 4 and a path $P$ such that $G\subseteq H \boxtimes P \boxtimes K_{\max\{2g,3\}}$. We improve
Marc Distel   +3 more
doaj   +1 more source

An SPQR-tree-like embedding representation for level planarity

open access: yesJournal of Computational Geometry, 2023
An SPQR-tree is a data structure that efficiently represents all planar embeddings of a  connected planar graph. It is a key tool in a number of constrained planarity testing algorithms, which seek a planar embedding of a graph subject to some given set
Guido Brückner, Ignaz Rutter
doaj   +1 more source

On the planarity of line Mycielskian graph of a graph

open access: yesRatio Mathematica, 2020
The line Mycielskian graph of a graph G, denoted by Lμ(G) is defined as the graph obtained from L(G) by adding q+1 new vertices E' = ei' : 1 ≤  i ≤  q and e, then for 1 ≤  i ≤  q , joining ei' to the neighbours of ei  and  to e.
Keerthi G. Mirajkar   +1 more
doaj   +1 more source

On the planar edge-length ratio of planar graphs

open access: yesJournal of Computational Geometry, 2020
The edge-length ratio of a straight-line drawing of a graph is the ratio between the lengths of the longest and of the shortest edge in the drawing. The planar edge-length ratio of a planar graph is the minimum edge-length ratio of any planar straight ...
Manuel Borrazzo, Fabrizio Frati
doaj   +1 more source

Equitable Coloring of IC-Planar Graphs with Girth g ≥ 7

open access: yesAxioms, 2023
An equitable k-coloring of a graph G is a proper vertex coloring such that the size of any two color classes differ at most 1. If there is an equitable k-coloring of G, then the graph G is said to be equitably k-colorable.
Danjun Huang, Xianxi Wu
doaj   +1 more source

Relaxed DP-Coloring and another Generalization of DP-Coloring on Planar Graphs without 4-Cycles and 7-Cycles

open access: yesDiscussiones Mathematicae Graph Theory, 2023
DP-coloring is generalized via relaxed coloring and variable degeneracy in [P. Sittitrai and K. Nakprasit, Su cient conditions on planar graphs to have a relaxed DP-3-coloring, Graphs Combin. 35 (2019) 837–845], [K.M. Nakprasit and K.
Sribunhung Sarawute   +3 more
doaj   +1 more source

A note on nearly Platonic graphs with connectivity one

open access: yesElectronic Journal of Graph Theory and Applications, 2021
A k-regular planar graph G is nearly Platonic when all faces but one are of the same degree while the remaining face is of a different degree. We show that no such graphs with connectivity one can exist. This complements a recent result by Keith, Froncek,
Dalibor Froncek   +3 more
doaj   +1 more source

Drawing planar graphs with many collinear vertices

open access: yesJournal of Computational Geometry, 2018
Consider the following problem: Given a planar graph $G$, what is the maximum number $p$ such that $G$ has a planar straight-line drawing with $p$ collinear vertices?
Giordano Da Lozzo   +4 more
doaj   +1 more source

SOME PROPERTIES ON COPRIME GRAPH OF GENERALIZED QUATERNION GROUPS

open access: yesBarekeng, 2023
A coprime graph is a representation of finite groups on graphs by defining the vertex graph as an element in a group and two vertices adjacent to each other's if and only if the order of the two elements is coprime.
Arif Munandar
doaj   +1 more source

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