Results 71 to 80 of about 259 (109)

Reconfiguring Minimum Dominating Sets: The γ-Graph of a Tree

open access: yesDiscussiones Mathematicae Graph Theory, 2018
We consider γ-graphs, which are reconfiguration graphs of the minimum dominating sets of a graph G. We answer three open questions about γ- graphs of trees by providing upper bounds on the maximum degree, the diameter, and the number of minimum ...
Edwards Michelle   +2 more
doaj   +1 more source

On (k1A1, k2A2, k3A3)-Edge Colourings in Graphs and Generalized Jacobsthal Numbers

open access: yesAnnales Mathematicae Silesianae
In this paper we introduce a new kind of generalized Jacobsthal numbers in a distance sense. We give the identities and matrix representations for them and their connections with the Fibonacci and the Pell numbers. We also describe the interpretations of
Piejko Krzysztof, Trojnar-Spelina Lucyna
doaj   +1 more source

On The Co-Roman Domination in Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2019
Let G = (V, E) be a graph and let f : V (G) → {0, 1, 2} be a function. A vertex v is said to be protected with respect to f, if f(v) > 0 or f(v) = 0 and v is adjacent to a vertex of positive weight. The function f is a co-Roman dominating function if (i)
Shao Zehui   +4 more
doaj   +1 more source

A note on lower bounds for the total domination number of digraphs

open access: yes, 2017
A vertex subset S of a digraph D is called a dominating set of D if every vertex not in S is adjacent from at least one vertex in S. A dominating set S of D is called a total dominating set of D if the subdigraph of D induced by S has no isolated ...
Chen, Xiaodan, Hao, Guoliang
core  

Cubic Graphs with Total Domatic Number at Least Two

open access: yesDiscussiones Mathematicae Graph Theory, 2018
Let G be a graph with no isolated vertex. A total dominating set of G is a set S of vertices of G such that every vertex is adjacent to at least one vertex in S.
Akbari Saieed   +3 more
doaj   +1 more source

Global Italian domination in graphs

open access: yes, 2019
An Italian dominating function (IDF) on a graph G = (V,E) is a function f : V → f{0, 1, 2} satisfying the condition that for every vertex v ∈ V (G) with f(v) = 0, either v is adjacent to a vertex assigned 2 under f, or v is adjacent to at least two ...
Xu, Zhijun   +3 more
core  

Improved McClelland and Koolen-Moulton bounds for distance energy of a graph. [PDF]

open access: yesJ Inequal Appl, 2018
Sridhara G   +3 more
europepmc   +1 more source

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