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Author (up) de Figueiredo, C.M.H.; de Mello, C.P.; Ortiz, C.
Title Edge colouring reduced indifference graphs Type
Year 2000 Publication Lecture Notes in Computer Sciences Abbreviated Journal Lect. Notes Comput. Sc.
Volume 1776 Issue Pages 145-153
Keywords
Abstract The chromatic index problem – finding the minimum number of colours required for colouring the edges of a graph – is still unsolved for indifference graphs, whose vertices can be linearly ordered so that the vertices contained in the same maximal clique are consecutive in this order. Two adjacent vertices are twins if they belong to the same maximal cliques. A graph is reduced if it contains no pair of twin vertices. A graph is overfull if the total number of edges is greater than the product of the maximum degree by [n/2], where n is the number of vertices. We give a structural characterization for neighbourhood-over full indifference graphs proving that a reduced indifference graph cannot be neighbourhood-overfull. We show that the chromatic index for all reduced indifference graphs is the maximum degree.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0302-9743 ISBN Medium
Area Expedition Conference Latin 2000: Theoretical Informaticsture Notes in Computer Science
Notes WOS:000165335400016 Approved
Call Number UAI @ eduardo.moreno @ Serial 25
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Author (up) de Figueiredo, C.M.H.; Meldanis, J.; de Mello, C.P.; Ortiz, C.
Title Decompositions for the edge colouring of reduced indifference graphs Type
Year 2003 Publication Theoretical Computer Science Abbreviated Journal Theor. Comput. Sci.
Volume 297 Issue 1-3 Pages 145-155
Keywords
Abstract The chromatic index problem-finding the minimum number of colours required for colouring the edges of a graph-is still unsolved for indifference graphs, whose vertices can be linearly ordered so that the vertices contained in the same maximal clique are consecutive in this order. We present new positive evidence for the conjecture: every non neighbourhood-overfull indifference graph can be edge coloured with maximum degree colours. Two adjacent vertices are twins if they belong to the same maximal cliques. A graph is reduced if it contains no pair of twin vertices. A graph is overfull if the total number of edges is greater than the product of the maximum degree by [n/2], where n is the number of vertices. We give a structural characterization for neighbourhood-overfull indifference graphs proving that a reduced indifference graph cannot be neighbourhood-overfull. We show that the chromatic index for all reduced indifference graphs is the maximum degree. We present two decomposition methods for edge colouring reduced indifference graphs with maximum degree colours. (C) 2002 Elsevier Science B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3975 ISBN Medium
Area Expedition Conference
Notes WOS:000181732700008 Approved
Call Number UAI @ eduardo.moreno @ Serial 24
Permanent link to this record