Results 21 to 30 of about 34,455 (233)
Operations Research and Decisions, 2016 OPERATIONS RESEARCH AND DECISIONS; ISSN 2081 ...
Peters, Hans +2 more
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Double vertex digraphs of digraphs
Discrete Mathematics, 2009 AbstractLet D be a digraph of order n. The double vertex digraph S2(D) of D is the digraph whose vertex set consists of all ordered pairs of distinct vertices of V(D) such that there is an arc in S2(D) from (x,y) to (u,v) if and only if x=u and there is an arc in D from y to v, or y=v and there is an arc in D from x to u.
Yanling Shao, Yubin Gao
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Journal of Combinatorial Theory, Series B, 2017 An antidirected trail in a digraph is a trail (a walk with no arc repeated) in which the arcs alternate between forward and backward arcs. An antidirected path is an antidirected trail where no vertex is repeated. We show that it is NP-complete to decide whether two vertices $x,y$ in a digraph are connected by an antidirected path, while one can decide
Bang-Jensen, Jørgen +3 more
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On some subclasses of interval catch digraphs
Electronic Journal of Graph Theory and Applications, 2022 A digraph G = (V, E) is an interval catch digraph if for each vertex v ∈ V, one can associate an interval on real line and a point within it (say (Iv, pv)) in such a way that uv ∈ E if and only if pv ∈ Iu. It was introduced by Maehara in 1984.
Sanchita Paul, Shamik Ghosh
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Discrete Mathematics, 1997 ``This paper focuses on a family of vertex symmetric digraphs \dots which were introduced by \textit{M. L. Fiol} [The relation between digraphs and groups through Cayley digraphs, Universitat Autònoma de Barcelona, 1984 (in Catalan)].'' For integers \(k\) and \(n\), \(1\leq k\leq n-1\), a digraph \(P(n,k)\) has as vertices the \(k\)-permutations of ...
Josep M. Brunat +2 more
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The non-negative spectrum of a digraph
Open Mathematics, 2020 Given the adjacency matrix A of a digraph, the eigenvalues of the matrix AAT constitute the so-called non-negative spectrum of this digraph. We investigate the relation between the structure of digraphs and their non-negative spectra and associated ...
Alomari Omar +2 more
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Discrete Mathematics, 2004 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Boland, James +2 more
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AKCE International Journal of Graphs and Combinatorics, 2020 Let and be two digraphs; without loops or multiple arcs. An coloring of is a function . We say that is an colored digraph. For an arc of , we say that is the color of over the coloring . A directed path in is an path if is a directed walk in .
Hortensia Galeana-Sánchez +1 more
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Theoretical Computer Science, 2010 AbstractWe re-consider perfect elimination digraphs, that were introduced by Haskins and Rose in 1973, and view these graphs as directed analogues of chordal graphs. Several structural properties of chordal graphs that are crucial for algorithmic applications carry over to the directed setting, including notions like simplicial vertices, perfect ...
Daniel Meister, Jan Arne Telle
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Arc-Disjoint Hamiltonian Cycles in Round Decomposable Locally Semicomplete Digraphs
Discussiones Mathematicae Graph Theory, 2018 Let D = (V,A) be a digraph; if there is at least one arc between every pair of distinct vertices of D, then D is a semicomplete digraph. A digraph D is locally semicomplete if for every vertex x, the out-neighbours of x induce a semicomplete digraph and ...
Li Ruijuan, Han Tingting
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