Results 71 to 80 of about 584,165 (157)

Edge covering pseudo-outerplanar graphs with forests [PDF]

open access: yes, 2012
A graph is pseudo-outerplanar if each block has an embedding on the plane in such a way that the vertices lie on a fixed circle and the edges lie inside the disk of this circle with each of them crossing at most one another.
Zhang, Xin, Liu, Guizhen, Wu, Jian-Liang
core   +1 more source

On tree decompositions whose trees are minors

open access: yesJournal of Graph Theory, Volume 106, Issue 2, Page 296-306, June 2024.
Abstract In 2019, Dvořák asked whether every connected graph G $G$ has a tree decomposition ( T , B ) $(T,{\rm{ {\mathcal B} }})$ so that T $T$ is a subgraph of G $G$ and the width of ( T , B ) $(T,{\rm{ {\mathcal B} }})$ is bounded by a function of the treewidth of G $G$.
Pablo Blanco   +5 more
wiley   +1 more source

Star Coloring Outerplanar Bipartite Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2019
A proper coloring of the vertices of a graph is called a star coloring if at least three colors are used on every 4-vertex path. We show that all outerplanar bipartite graphs can be star colored using only five colors and construct the smallest known ...
Ramamurthi Radhika, Sanders Gina
doaj   +1 more source

Approximation Algorithms for the Maximum Induced Planar and Outerplanar Subgraph Problems

open access: yesJournal of Graph Algorithms and Applications, 2007
The task of finding the largest subset of vertices of a graph that induces a planar subgraph is known as the Maximum Induced Planar Subgraph problem (MIPS). In this paper, some new approximation algorithms for MIPS are introduced.
Kerri Morgan, Graham Farr
doaj   +1 more source

The product structure of squaregraphs

open access: yesJournal of Graph Theory, Volume 105, Issue 2, Page 179-191, February 2024.
Abstract A squaregraph is a plane graph in which each internal face is a 4‐cycle and each internal vertex has degree at least 4. This paper proves that every squaregraph is isomorphic to a subgraph of the semistrong product of an outerplanar graph and a path.
Robert Hickingbotham   +3 more
wiley   +1 more source

On Vertices Enforcing a Hamiltonian Cycle

open access: yesDiscussiones Mathematicae Graph Theory, 2013
A nonempty vertex set X ⊆ V (G) of a hamiltonian graph G is called an H-force set of G if every X-cycle of G (i.e. a cycle of G containing all vertices of X) is hamiltonian.
Fabrici Igor   +2 more
doaj   +1 more source

Maximal outerplanar graphs as chordal graphs, path-neighborhood graphs, and triangle graphs [PDF]

open access: yes
Maximal outerplanar graphs are characterized using three different classes of graphs. A path-neighborhood graph is a connected graph in which every neighborhood induces a path. The triangle graph $T(G)$ has the triangles of the graph $G$ as its vertices,
Novick, B., Laskar, R.C., Mulder, H.M.
core  

Upward Planarity Testing of Outerplanar Dags (Extended Abstract)

open access: yes, 1995
In this paper, we present two polynomial-time algorithms to determine if an outerplanar directed acyclic graph (odag) can be drawn upward planar, that is, drawn in planar straight-line fashion so that all arcs point up.
Papakostas, Achilleas   +1 more
core   +1 more source

Improved Bounds for Track Numbers of Planar Graphs

open access: yesJournal of Graph Algorithms and Applications, 2020
A track layout of a graph consists of a vertex coloring and a total order of each color class, such that no two edges cross between any two color classes.
Sergey Pupyrev
doaj   +1 more source

A fast parallel algorithm for optimal edge-colouring of outerplanar graphs [PDF]

open access: yes
We prove that every outerplanar graph can be optimally edge-coloured in polylog time using a polynomial number of processors on a parallel random access machine without write conflicts (P-RAM)
Gibbons, Alan (Alan M.)   +1 more
core  

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