Results 31 to 40 of about 2,666,039 (345)

Colouring of plane graphs with unique maximal colours on faces [PDF]

open access: yes, 2015
The Four Colour Theorem asserts that the vertices of every plane graph can be properly coloured with four colors. Fabrici and G\"oring conjectured the following stronger statement to also hold: the vertices of every plane graph can be properly coloured ...
Wendland, Alex
core   +2 more sources

Graph polynomials and paintability of plane graphs

open access: yesDiscrete Applied Mathematics, 2022
There exists a variety of coloring problems for plane graphs, involving vertices, edges, and faces in all possible combinations. For instance, in the \emph{entire coloring} of a plane graph we are to color these three sets so that any pair of adjacent or incident elements get different colors.
Jarosław Grytczuk   +2 more
openaire   +2 more sources

Improved Bounds for Some Facially Constrained Colorings

open access: yesDiscussiones Mathematicae Graph Theory, 2023
A facial-parity edge-coloring of a 2-edge-connected plane graph is a facially-proper edge-coloring in which every face is incident with zero or an odd number of edges of each color. A facial-parity vertex-coloring of a 2-connected plane graph is a proper
Štorgel Kenny
doaj   +1 more source

BgNet: Classification of benign and malignant tumors with MRI multi-plane attention learning

open access: yesFrontiers in Oncology, 2022
ObjectivesTo propose a deep learning-based classification framework, which can carry out patient-level benign and malignant tumors classification according to the patient’s multi-plane images and clinical information.MethodsA total of 430 cases of spinal
Hong Liu   +17 more
doaj   +1 more source

On the Plane-Width of Graphs

open access: yesElectronic Notes in Discrete Mathematics, 2009
Map vertices of a graph to (not necessarily distinct) points of the plane so that two adjacent vertices are mapped at least a unit distance apart. The plane-width of a graph is the minimum diameter of the image of the vertex set over all such mappings.
Kaminski, Marcin   +2 more
openaire   +3 more sources

Counting Plane Graphs: Cross-Graph Charging Schemes [PDF]

open access: yesCombinatorics, probability & computing, 2012
We study cross-graph charging schemes for graphs drawn in the plane. These are charging schemes where charge is moved across vertices of different graphs.
M. Sharir, Adam Sheffer
semanticscholar   +1 more source

Flat Foldings of Plane Graphs with Prescribed Angles and Edge Lengths [PDF]

open access: yes, 2018
When can a plane graph with prescribed edge lengths and prescribed angles (from among $\{0,180^\circ, 360^\circ$\}) be folded flat to lie in an infinitesimally thin line, without crossings?
Abel, Zachary   +5 more
core   +2 more sources

Splitting Plane Graphs to Outerplanarity

open access: yesJournal of Graph Algorithms and Applications, 2023
Vertex splitting replaces a vertex by two copies and partitions its incident edges amongst the copies. This problem has been studied as a graph editing operation to achieve desired properties with as few splits as possible, most often planarity, for which the problem is NP-hard.Here we study how to minimize the number of splits to turn a plane graph ...
Gronemann, Martin   +2 more
openaire   +2 more sources

A Penrose polynomial for embedded graphs [PDF]

open access: yes, 2011
We extend the Penrose polynomial, originally defined only for plane graphs, to graphs embedded in arbitrary surfaces. Considering this Penrose polynomial of embedded graphs leads to new identities and relations for the Penrose polynomial which can not be
Aigner   +22 more
core   +4 more sources

A plane graph representation of triconnected graphs

open access: yesTheoretical Computer Science, 2010
AbstractGiven a graph G=(V,E), a set S={s1,s2,…,sk} of k vertices of V, and k natural numbers n1,n2,…,nk such that ∑i=1kni=|V|, the k-partition problem is to find a partition V1,V2,…,Vk of the vertex set V such that |Vi|=ni, si∈Vi, and Vi induces a connected subgraph of G for each i=1,2,…,k. For the tripartition problem on a triconnected graph, a naive
Hiroshi Nagamochi   +2 more
openaire   +2 more sources

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