Results 1 to 10 of about 846 (94)
On L(2, 1)-Labelings of Oriented Graphs
Discussiones Mathematicae Graph Theory, 2022 We extend a result of Griggs and Yeh about the maximum possible value of the L(2, 1)-labeling number of a graph in terms of its maximum degree to oriented graphs.
Colucci Lucas, Győri Ervin
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Ascending Subgraph Decompositions of Oriented Graphs that Factor into Triangles
Discussiones Mathematicae Graph Theory, 2022 In 1987, Alavi, Boals, Chartrand, Erdős, and Oellermann conjectured that all graphs have an ascending subgraph decomposition (ASD). In a previous paper, Wagner showed that all oriented complete balanced tripartite graphs have an ASD.
Austin Andrea D., Wagner Brian C.
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Extremal Digraphs Avoiding Distinct Walks of Length 4 with the Same Endpoints
Discussiones Mathematicae Graph Theory, 2022 Let n ≥ 8 be an integer. We characterize the extremal digraphs of order n with the maximum number of arcs avoiding distinct walks of length 4 with the same endpoints.
Lyu Zhenhua
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Extremal digraphs on Meyniel-type condition for hamiltonian cycles in balanced bipartite digraphs [PDF]
Discrete Mathematics & Theoretical Computer Science, 2022 Let $D$ be a strong balanced digraph on $2a$ vertices. Adamus et al. have proved that $D$ is hamiltonian if $d(u)+d(v)\ge 3a$ whenever $uv\notin A(D)$ and $vu\notin A(D)$. The lower bound $3a$ is tight.
Ruixia Wang, Linxin Wu, Wei Meng
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A Note on Edge-Group Choosability of Planar Graphs without 5-Cycles
Journal of Mathematics, 2020 This paper is devoted to a study of the concept of edge-group choosability of graphs. We say that G is edge-k-group choosable if its line graph is k-group choosable.
Amir Khamseh
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Discussiones Mathematicae Graph Theory, 2022 We introduce a new notion of circular colourings for digraphs. The idea of this quantity, called star dichromatic number χ→*\vec \chi * (D) of a digraph D, is to allow a finer subdivision of digraphs with the same dichromatic number into such which are ...
Hochstättler Winfried, Steiner Raphael
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Hamiltonian Cycle Problem in Strong k-Quasi-Transitive Digraphs With Large Diameter
Discussiones Mathematicae Graph Theory, 2021 Let k be an integer with k ≥ 2. A digraph is k-quasi-transitive, if for any path x0x1... xk of length k, x0 and xk are adjacent. Let D be a strong k-quasi-transitive digraph with even k ≥ 4 and diameter at least k +2.
Wang Ruixia
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H-Kernels in Unions of H-Colored Quasi-Transitive Digraphs
Discussiones Mathematicae Graph Theory, 2021 Let H be a digraph (possibly with loops) and D a digraph without loops whose arcs are colored with the vertices of H (D is said to be an H-colored digraph). For an arc (x, y) of D, its color is denoted by c(x, y). A directed path W = (v0, . .
Campero-Alonzo José Manuel +1 more
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A method to determine algebraically integral Cayley digraphs on finite Abelian group [PDF]
, 2018 Researchers in the past have studied eigenvalues of Cayley digraphs or graphs. We are interested in characterizing Cayley digraphs on a finite Abelian group G whose eigenvalues are algebraic integers in a given number field K. And we succeed in finding a
Li, Fei
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Minimally Strong Subgraph (k,ℓ)-Arc-Connected Digraphs
Discussiones Mathematicae Graph Theory, 2022 Let D = (V,A) be a digraph of order n, S a subset of V of size k and 2 ≤ k ≤ n. A subdigraph H of D is called an S-strong subgraph if H is strong and S ⊆ V (H). Two S-strong subgraphs D1 and D2 are said to be arc-disjoint if A(D1) ∩ A(D2) = ∅.
Sun Yuefang, Jin Zemin
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