Kernels in the closure of coloured digraphs
Hortensia Galeana-Sánchez ; José de Jesús García-Ruvalcaba
Discussiones Mathematicae Graph Theory, Tome 20 (2000), p. 243-254 / Harvested from The Polish Digital Mathematics Library

Let D be a digraph with V(D) and A(D) the sets of vertices and arcs of D, respectively. A kernel of D is a set I ⊂ V(D) such that no arc of D joins two vertices of I and for each x ∈ V(D)∖I there is a vertex y ∈ I such that (x,y) ∈ A(D). A digraph is kernel-perfect if every non-empty induced subdigraph of D has a kernel. If D is edge coloured, we define the closure ξ(D) of D the multidigraph with V(ξ(D)) = V(D) and A(ξ(D))=i(u,v)withcolourithereexistsamonochromaticpathofcolourifromthevertexutothevertexvcontainedinD.Let T₃ and C₃ denote the transitive tournament of order 3 and the 3-cycle, respectively, both of whose arcs are coloured with 3 different colours. In this paper, we survey sufficient conditions for the existence of kernels in the closure of edge coloured digraphs, also we prove that if D is obtained from an edge coloured tournament by deleting one arc and D does not contain T₃ or C₃, then ξ(D) is a kernel-perfect digraph.

Publié le : 2000-01-01
EUDML-ID : urn:eudml:doc:270579
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     title = {Kernels in the closure of coloured digraphs},
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Hortensia Galeana-Sánchez; José de Jesús García-Ruvalcaba. Kernels in the closure of coloured digraphs. Discussiones Mathematicae Graph Theory, Tome 20 (2000) pp. 243-254. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_7151_dmgt_1123/

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