Results 11 to 20 of about 34,455 (233)
Cospectral digraphs from locally line digraphs [PDF]
Linear Algebra and its Applications, 2016 A digraph $\G=(V,E)$ is a line digraph when every pair of vertices $u,v\in V$ have either equal or disjoint in-neighborhoods. When this condition only applies for vertices in a given subset (with at least two elements), we say that $\G$ is a locally line
Dalfó, C., Fiol, M. A.
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Digraph Decompositions and Monotonicity in Digraph Searching [PDF]
Theoretical Computer Science, 2008 We consider monotonicity problems for graph searching games. Variants of these games - defined by the type of moves allowed for the players - have been found to be closely connected to graph decompositions and associated width measures such as path- or tree-width. Of particular interest is the question whether these games are monotone, i.e. whether the
Kreutzer, S, Ordyniak, S
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Journal of Research of the National Institute of Standards and Technology, 2014 A digraph whose degree sequence has a unique vertex labeled realization is called threshold. In this paper we present several characterizations of threshold digraphs and their degree sequences, and show these characterizations to be equivalent. One of the characterizations is new, and allows for a shorter proof of the equivalence of the two known ...
M. Drew LaMar +3 more
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On Packing Dijoins in Digraphs and Weighted Digraphs
SIAM Journal on Discrete Mathematics, 2023 Let $D=(V,A)$ be a digraph. A dicut is a cut $δ^+(U)\subseteq A$ for some nonempty proper vertex subset $U$ such that $δ^-(U)=\emptyset$, a dijoin is an arc subset that intersects every dicut at least once, and more generally a $k$-dijoin is an arc subset that intersects every dicut at least $k$ times.
Abdi, Ahmad +2 more
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Immersion of complete digraphs in Eulerian digraphs
Israel Journal of Mathematics, 2023 AbstractA digraph G immerses a digraph H if there is an injection f: V(H) → V(G) and a collection of pairwise edge-disjoint directed paths Puv, for uv ∈ E(H), such that Puv starts at f(u) and ends at f(v). We prove that every Eulerian digraph with minimum out-degree t immerses a complete digraph on Ω(t) vertices, thus answering a question of DeVos ...
Letzter, Shoham, Girão, António
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On the Italian reinforcement number of a digraph
AIMS Mathematics, 2021 The Italian reinforcement number of a digraph is the minimum number of arcs that have to be added to the digraph in order to decrease the Italian domination number. In this paper, we present some new sharp upper bounds on the Italian reinforcement number
Zhihong Xie +2 more
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Generalized Neutrosophic Competition Graphs [PDF]
Neutrosophic Sets and Systems, 2020 The generalized neutrosophic graph is a generalization of the neutrosophic graph that represents a system perfectly. In this study, the concept of a neutrosophic digraph, generalized neutrosophic digraph and out-neighbourhood of a vertex of a ...
Kousik Das, Sovan Samanta, Kajal De
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Bounds for the skew Laplacian (skew adjacency) spectral radius of a digraph [PDF]
Transactions on Combinatorics, 2019 For a simple connected graph $G$ with $n$ vertices and $m$ edges, let $\overrightarrow{G}$ be a digraph obtained by giving an arbitrary direction to the edges of $G$.
Hilal A. Ganie
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