Results 51 to 60 of about 7,042,445 (296)
Protection of Lexicographic Product Graphs
Discussiones Mathematicae Graph Theory, 2022 In this paper, we study the weak Roman domination number and the secure domination number of lexicographic product graphs. In particular, we show that these two parameters coincide for almost all lexicographic product graphs. Furthermore, we obtain tight
Klein Douglas J. +1 more
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Total domination and least domination in a tree
Discrete Mathematics, 2003 A subset \(X\) of the vertex set \(V(G)\) of a graph \(G\) is called dominating (or total dominating) in \(G\), if for each \(x\in V(G)- X\) (or for each \(x\in V(G)\), respectively) there exists \(y\in X\) adjacent to \(x\). The least number of vertices of a dominating (or total dominating) set in \(G\) is the domination number \(\gamma(G)\) (or the ...
Xuezheng Lv, Jingzhong Mao
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Properties of the Global Total k-Domination Number
Mathematics, 2021 A nonempty subset D⊂V of vertices of a graph G=(V,E) is a dominating set if every vertex of this graph is adjacent to at least one vertex from this set except the vertices which belong to this set itself.
Frank A. Hernández Mira +3 more
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Total Domination on Some Graph Operators
Mathematics, 2021 Let G=(V,E) be a graph; a set D⊆V is a total dominating set if every vertex v∈V has, at least, one neighbor in D. The total domination number γt(G) is the minimum cardinality among all total dominating sets.
José M. Sigarreta
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Some notes on the isolate domination in graphs
AKCE International Journal of Graphs and Combinatorics, 2017 A subset of vertices of a graph is a dominating set of if every vertex in has a neighbor in . The domination number is the minimum cardinality of a dominating set of . A dominating set is an isolate dominating set if the induced subgraph has at least one
Nader Jafari Rad
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On the Complexity of Reinforcement in Graphs
Discussiones Mathematicae Graph Theory, 2016 We show that the decision problem for p-reinforcement, p-total rein- forcement, total restrained reinforcement, and k-rainbow reinforcement are NP-hard for bipartite graphs.
Rad Nader Jafari
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Total Roman Domination Number of Rooted Product Graphs
Mathematics, 2020 Let G be a graph with no isolated vertex and f:V(G)→{0,1,2} a function. If f satisfies that every vertex in the set {v∈V(G):f(v)=0} is adjacent to at least one vertex in the set {v∈V(G):f(v)=2}, and if the subgraph induced by the set {v∈V(G):f(v)≥1} has ...
Abel Cabrera Martínez +3 more
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On a conjecture concerning total domination subdivision number in graphs
AKCE International Journal of Graphs and Combinatorics, 2021 Let be the total domination number and let be the total domination subdivision number of a graph G with no isolated vertex. In this paper, we show that for some classes of graphs G, which partially solve the conjecture presented by Favaron et al.
S. Kosari +5 more
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Total 2-Rainbow Domination in Graphs
Mathematics, 2022 A total k-rainbow dominating function on a graph G=(V,E) is a function f:V(G)→2{1,2,…,k} such that (i) ∪u∈N(v)f(u)={1,2,…,k} for every vertex v with f(v)=∅, (ii) ∪u∈N(v)f(u)≠∅ for f(v)≠∅.
Huiqin Jiang, Yongsheng Rao
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Pediatric Blood &Cancer, EarlyView.ABSTRACT Background Loneliness is associated with adverse physical and mental health outcomes and remains understudied in children and adolescents undergoing cancer therapy. Pediatric oncology patients may be at increased risk due to medical isolation and disruption of social networks.
Charlotte N. Stahlfeld +5 more
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