Results 221 to 230 of about 1,437,233 (261)
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SIAM Journal on Discrete Mathematics, 1999
A property \(P\) of graphs is called monotone if it is preserved under the deletion of edges. Let \(\Delta^P_n\) denote the simplicial complex whose simplices are edge sets of \(n\)-vertex graphs having a monotone property \(P\). Topological properties of complexes of undirected graphs recently have been studied in a number of papers (see references in
Anders Björner, Volkmar Welker
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A property \(P\) of graphs is called monotone if it is preserved under the deletion of edges. Let \(\Delta^P_n\) denote the simplicial complex whose simplices are edge sets of \(n\)-vertex graphs having a monotone property \(P\). Topological properties of complexes of undirected graphs recently have been studied in a number of papers (see references in
Anders Björner, Volkmar Welker
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Software - Practice and Experience, 1987
AbstractA general‐purpose browser for directed graphs is described. The browser provides operations to examine and edit graphs and to generate a layout for a graph automatically that minimizes edge crossings. Two layout algorithms were implemented. A hierarchical graph layout algorithm was found to be best for directed graphs.
Lawrence Arnold Rowe
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AbstractA general‐purpose browser for directed graphs is described. The browser provides operations to examine and edit graphs and to generate a layout for a graph automatically that minimizes edge crossings. Two layout algorithms were implemented. A hierarchical graph layout algorithm was found to be best for directed graphs.
Lawrence Arnold Rowe
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SIAM Journal on Discrete Mathematics, 1999
A ranking of a (di)graph is a colouring of the vertex set with positive integers in such a way that every (di)path between two vertices of the same colour has a vertex of larger colour. The \(k\)-ranking problem is as follows: given a (di)graph \(G\) and an integer \(k\), check whether \(G\) has a ranking with \(k\) colours. This problem is known to be
Jan Kratochvíl, Zsolt Tuza
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A ranking of a (di)graph is a colouring of the vertex set with positive integers in such a way that every (di)path between two vertices of the same colour has a vertex of larger colour. The \(k\)-ranking problem is as follows: given a (di)graph \(G\) and an integer \(k\), check whether \(G\) has a ranking with \(k\) colours. This problem is known to be
Jan Kratochvíl, Zsolt Tuza
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Journal of Graph Theory, 1992
AbstractWe give a new condition involving degrees sufficient for a digraph to be hamiltonian.
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AbstractWe give a new condition involving degrees sufficient for a digraph to be hamiltonian.
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Independent Directed Triangles in a Directed Graph
Graphs and Combinatorics, 2000zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Information Processing Letters, 2002
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Alan J. Hoffman +2 more
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zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Alan J. Hoffman +2 more
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SIAM Journal on Algebraic Discrete Methods, 1985
This very interesting paper introduces the concept of graceful directed graphs as follows. A digraph D with e arcs is numbered by assigning a distinct integer value h(v) from \(\{\) 0,1,...,e\(\}\) to each node v. Each arc (u,v) receives a value \(h(u,v)=h(v)-h(u)\) (mod e\(+1)\).
Bloom, G. S., Hsu, D. F.
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This very interesting paper introduces the concept of graceful directed graphs as follows. A digraph D with e arcs is numbered by assigning a distinct integer value h(v) from \(\{\) 0,1,...,e\(\}\) to each node v. Each arc (u,v) receives a value \(h(u,v)=h(v)-h(u)\) (mod e\(+1)\).
Bloom, G. S., Hsu, D. F.
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Decomposition of Directed Graphs
SIAM Journal on Algebraic Discrete Methods, 1982A composition for directed graphs which generalizes the substitution (or X-join) composition of graphs and digraphs, as well as the graph version of set-family composition, is described. It is proved that a general decomposition theory can be applied to the resulting digraph decomposition.
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On the Group of a Directed Graph
Canadian Journal of Mathematics, 1966In 1938, Frucht (2) proved that for any given finite group G there exists a finite symmetric graph X such that G(X) is abstractly isomorphic to G. Since G(X) is a permutation group, it is natural to ask the following related question : If P is a given finite permutation group, does there exist a symmetric (and more generally a directed) graph X such ...
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Networks, 2008
AbstractThe concept of persistent directed graphs was introduced by Hendrickx et al. to help analyze the stability of autonomous agent systems. They provided a combinatorial characterization for persistence but the complexity of testing persistence remained open.
Jørgen Bang-Jensen, Tibor Jordán
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AbstractThe concept of persistent directed graphs was introduced by Hendrickx et al. to help analyze the stability of autonomous agent systems. They provided a combinatorial characterization for persistence but the complexity of testing persistence remained open.
Jørgen Bang-Jensen, Tibor Jordán
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