Results 41 to 50 of about 107 (98)
Sufficient Conditions for a Digraph to Admit A (1, ≤ ℓ)-Identifying Code
Discussiones Mathematicae Graph Theory, 2021 A (1, ≤ ℓ)-identifying code in a digraph D is a subset C of vertices of D such that all distinct subsets of vertices of cardinality at most ℓ have distinct closed in-neighbourhoods within C. In this paper, we give some sufficient conditions for a digraph
Balbuena Camino +2 more
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Traffic and Emergency Network Optimisation Using Domination in Picture Fuzzy Directed Graphs
Journal of Mathematics, Volume 2026, Issue 1, 2026.In this paper, the picture fuzzy digraphs PFDGs are analysed in depth concerning their domination number (DN) and connectedness, offering new insights into structural properties and decision‐making approaches for handling uncertainty. Picture fuzzy sets (PFS) are a generalisation of traditional intuitionistic fuzzy sets, which provide a mathematical ...
J. Shivangi Mishra +6 more
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A digraph equation for homomorphic images
International Journal of Mathematics and Mathematical Sciences, Volume 9, Issue 2, Page 409-411, 1986., 1986 The definitions of a homomorphism and a contraction of a graph are generalized to digraphs. Solutions are given to the graph equation .
Robert D. Girse, Richard A. Gillman
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On characteristic and permanent polynomials of a matrix
Special Matrices, 2017 There is a digraph corresponding to every square matrix over ℂ. We generate a recurrence relation using the Laplace expansion to calculate the characteristic and the permanent polynomials of a square matrix.
Singh Ranveer, Bapat R. B.
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On kernels by rainbow paths in arc-coloured digraphs
Open Mathematics, 2021 In 2018, Bai, Fujita and Zhang [Discrete Math. 341 (2018), no. 6, 1523–1533] introduced the concept of a kernel by rainbow paths (for short, RP-kernel) of an arc-coloured digraph DD, which is a subset SS of vertices of DD such that (aa) there exists no ...
Li Ruijuan, Cao Yanqin, Zhang Xinhong
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The (1, 2)-step competition graph of a hypertournament
Open Mathematics, 2021 In 2011, Factor and Merz [Discrete Appl. Math. 159 (2011), 100–103] defined the (1,2)\left(1,2)-step competition graph of a digraph. Given a digraph D=(V,A)D=\left(V,A), the (1,2)\left(1,2)-step competition graph of D, denoted C1,2(D){C}_{1,2}\left(D ...
Li Ruijuan, An Xiaoting, Zhang Xinhong
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Signed Total Roman Domination in Digraphs
Discussiones Mathematicae Graph Theory, 2017 Let D be a finite and simple digraph with vertex set V (D). A signed total Roman dominating function (STRDF) on a digraph D is a function f : V (D) → {−1, 1, 2} satisfying the conditions that (i) ∑x∈N−(v)f(x) ≥ 1 for each v ∈ V (D), where N−(v) consists ...
Volkmann Lutz
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Path homology theory of edge-colored graphs
Open Mathematics, 2021 In this paper, we introduce the category and the homotopy category of edge-colored digraphs and construct the functorial homology theory on the foundation of the path homology theory provided by Grigoryan, Muranov, and Shing-Tung Yau.
Muranov Yuri V., Szczepkowska Anna
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, 1991 International Journal of Mathematics and Mathematical Sciences, Volume 16, Issue 3, Page 579-586, 1993.
Garry Johns, Karen Sleno
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Discussiones Mathematicae Graph Theory, 2018 A digraph is called irregular if its distinct vertices have distinct degree pairs. An irregular digraph is called minimal (maximal) if the removal of any arc (addition of any new arc) results in a non-irregular digraph. It is easily seen that the minimum
Górska Joanna +4 more
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