Results 61 to 70 of about 124 (114)
Niche Hypergraphs of Products of Digraphs
Discussiones Mathematicae Graph Theory, 2020 If D = (V, A) is a digraph, its niche hypergraph Nℋ(D) = (V, ℰ) has the edge set ℰ={e⊆V||e|≥2∧∃ υ∈V:e=ND−(υ)∨e=ND+(υ)}{\cal E} = \{ {e \subseteq V| | e | \ge 2 \wedge \exists \, \upsilon \in V:e = N_D^ - ( \upsilon ) \vee e = N_D^ + ( \upsilon ...
Sonntag Martin, Teichert Hanns-Martin
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Some Results on 4-Transitive Digraphs
Discussiones Mathematicae Graph Theory, 2017 Let D be a digraph with set of vertices V and set of arcs A. We say that D is k-transitive if for every pair of vertices u, v ∈ V, the existence of a uv-path of length k in D implies that (u, v) ∈ A.
García-Vázquez Patricio Ricardo +1 more
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Super Edge-Connectivity and Zeroth-Order Randić Index
Discussiones Mathematicae Graph Theory, 2020 Define the zeroth-order Randić index as R0(G)=∑x∈V(G)1dG(x),{R^0}\left( G \right) = \sum\nolimits_{x \in V\left( G \right)} {{1 \over {\sqrt {{d_G}} \left( x \right)}},} where dG(x) denotes the degree of the vertex x.
He Zhihong, Lu Mei
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𝕮-inverse of graphs and mixed graphs
Open MathematicsThis article introduces a generalization of the concept of inverse graphs applicable to both graphs and mixed graphs. Given a graph GG with adjacency matrix A(G)A\left(G), the inverse graph G−1{G}^{-1} is defined such that its adjacency matrix is similar
Alomari Omar +2 more
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γ-Inverse graph of some mixed graphs
Special MatricesLet GG be a graph. Then, the inverse graph G−1{G}^{-1} of GG is defined to be a graph that has adjacency matrix similar to the inverse of the adjacency matrix of GG, where the similarity matrix is ±1\pm 1 diagonal matrix. In this article, we introduced a
Boulahmar Wafa +2 more
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© Hindawi Publishing Corp. AN ALGEBRAIC FRAMEWORK OF WEIGHTED DIRECTED GRAPHS
, 2003 We show that an algebraic formulation of weighted directed graphs leads to in-troducing a k-vector space equipped with two coproducts ∆ and ∆ ̃ verifying the so-called coassociativity breaking equation (∆̃ ⊗ id) ∆ = (id⊗∆)∆̃. Such a space is called an L-
Philippe Leroux
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Causal structure learning in directed, possibly cyclic, graphical models
Journal of Causal InferenceWe consider the problem of learning a directed graph G⋆{G}^{\star } from observational data. We assume that the distribution that gives rise to the samples is Markov and faithful to the graph G⋆{G}^{\star } and that there are no unobserved variables.
Semnani Pardis, Robeva Elina
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, 2008 Hat problems have become a popular topic in recreational mathematics. In a typical hat problem, each of n players tries to guess the color of the hat they are wearing by looking at the colors of the hats worn by some of the other players.
Steven Butler +4 more
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γ-Cycles In Arc-Colored Digraphs
Discussiones Mathematicae Graph Theory, 2016 We call a digraph D an m-colored digraph if the arcs of D are colored with m colors. A directed path (or a directed cycle) is called monochromatic if all of its arcs are colored alike.
Galeana-Sánchez Hortensia +2 more
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On the sum of the total domination numbers of a diagraph and its converse
, 2019 A vertex subset S of a digraph D is called a dominating set of D if every vertex not in S has an in-neighbor in S. A dominating set S of D is called a total dominating set of D if the subdigraph induced by S has no isolated vertices. The total domination
Xie, Zhihong +2 more
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