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Optimal edge‐coloring with edge rate constraints
Author(s) -
Dereniowski Dariusz,
Kubiak Wieslaw,
Ries Bernard,
Zwols Yori
Publication year - 2013
Publication title -
networks
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.977
H-Index - 64
eISSN - 1097-0037
pISSN - 0028-3045
DOI - 10.1002/net.21505
Subject(s) - combinatorics , time complexity , mathematics , discrete mathematics , indifference graph , pooling , sequence (biology) , matching (statistics) , chordal graph , pathwidth , computer science , graph , line graph , statistics , artificial intelligence , biology , genetics
We consider the problem of covering the edges of a graph by a sequence of matchings subject to the constraint that each edge e appears in at least a given fraction r ( e ) of the matchings. Although it can be determined in polynomial time whether such a sequence of matchings exists or not [Grötschel et al., Combinatorica (1981), 169–197], we show that several questions about the length of the sequence are computationally intractable. Therefore, as is commonly done [Golumbic, Algorithmic graph theory and perfect graphs, 2004], we restrict our investigation to a special class of graphs. In recent work [Birand et al., INFOCOM 2010 Proceedings, 2010], two of the authors dealt with so‐called OLoP ( Overall Local Pooling ) graphs, a class of graphs for which similar matching‐related problems are tractable (namely, in an online distributed wireless network scheduling setting). We therefore focus on these graphs and generalize the results to a larger class of graphs which we call GOLoP graphs. In particular, we show that deciding whether a given GOLoP graph has a matching sequence of length at most k can be done in linear time. In case the answer is affirmative, we show how to construct, in quadratic time, the matching sequence of length at most k . Finally, we prove that, for GOLoP graphs, the length of a shortest sequence does not exceed a constant times the least common denominator of the fractions r ( e ), leading to a pseudopolynomial‐time algorithm for minimizing the length of the sequence. We show that the constant equals 1 for OLoP graphs and, following Seymour [Seymour, Proc. London Math. Soc., 1979], conjecture that the constant is as small as 2 for general graphs. We then show that this conjecture holds for all graphs with at most 10 vertices. © 2013 Wiley Periodicals, Inc. NETWORKS, Vol 62(3), 165–182 2013