Results 11 to 20 of about 8,914 (221)
The Electronic Journal of Combinatorics, 2011 We study digraphs preserved by a Maltsev operation: Maltsev digraphs. We show that these digraphs retract either onto a directed path or to the disjoint union of directed cycles, showing in this way that the constraint satisfaction problem for Maltsev digraphs is in logspace, L.
Catarina Carvalho +3 more
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Infinite digraphs isomorphic with their line digraphs [PDF]
Journal of Combinatorial Theory, Series B, 1976 In this paper we give a structural characterization of the digraphs that are isomorphic with their line digraphs.
Lowell W. Beineke, Robert L. Hemminger
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Discrete Mathematics, 1988 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
MARCHIORO P. +3 more
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From Subkautz Digraphs to Cyclic Kautz Digraphs [PDF]
Journal of Interconnection Networks, 2018 The Kautz digraphs K(d, ℓ) are a well-known family of dense digraphs, widely studied as a good model for interconnection networks. Closely related to these, the cyclic Kautz digraphs CK(d, ℓ) were recently introduced by Böhmová, Huemer and the author, and some of its distance-related parameters were fixed.
Dalfó Simó, Cristina
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European Journal of Combinatorics, 2006 zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Kaishun Wang, Yan-Quan Feng
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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 ...
Brian Cloteaux +3 more
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Digraphs on permutations [PDF]
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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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
doaj +2 more sources
On quotient digraphs and voltage digraphs [PDF]
, 2016 In this note we present a general approach to construct large digraphs from small ones. These are called expanded digraphs, and, as particular cases, we show their close relationship between voltage digraphs and line digraphs, which are two known approaches to obtain dense digraphs.
Dalfó Simó, Cristina +3 more
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Returnability in complex directed networks (digraphs) [PDF]
, 2008 The concept of returnability is proposed for complex directed networks (digraphs). It can be seen as a generalization of the concept of reciprocity. Two measures of the returnability are introduced. We establish closed formulas for the calculation of the
Estrada, Ernesto +5 more
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