TY - GEN
T1 - An O(log OPT)-approximation for covering/packing minor models of θr
AU - Chatzidimitriou, Dimitris
AU - Raymond, Jean Florent
AU - Sau, Ignasi
AU - Thilikos, Dimitrios M.
N1 - Publisher Copyright:
© Springer International Publishing Switzerland 2015.
PY - 2015
Y1 - 2015
N2 - Let CH be the class of graphs containing some fixed graph H as a minor. We define cv H(G) (resp. ce H(G)) as the minimun number of vertices (resp. edges) whose removal from G produces a graph without any subgraph isomorphic to a graph in CH. Also pv H(G) (resp. pe H(G)) is the the maximum number of vertex- (resp. edge-) disjoint subgraphs of G that are isomorphic to some graph in CH. We denote by θr the graph with two vertices and r parallel edges between them. When H = θr, the parameters cv/e H and pv/e H are NP-complete to compute (for sufficiently large r). In this paper we prove a series of combinatorial and algorithmic lemmata that imply that if pv/e θr (G) ≤ k, then cv/e θr (G) = O(k log k). This means that for every r, the class Cθr has the vertex/edge Erdős-Pósa property. Using the combinatorial ideas from our proofs we introduce a unified approach for the design of an O(log OPT)-approximation algorithm for cv θr, pv θr, ce θr and pe θr that runs in O(n ・ log(n) ・ m) steps.
AB - Let CH be the class of graphs containing some fixed graph H as a minor. We define cv H(G) (resp. ce H(G)) as the minimun number of vertices (resp. edges) whose removal from G produces a graph without any subgraph isomorphic to a graph in CH. Also pv H(G) (resp. pe H(G)) is the the maximum number of vertex- (resp. edge-) disjoint subgraphs of G that are isomorphic to some graph in CH. We denote by θr the graph with two vertices and r parallel edges between them. When H = θr, the parameters cv/e H and pv/e H are NP-complete to compute (for sufficiently large r). In this paper we prove a series of combinatorial and algorithmic lemmata that imply that if pv/e θr (G) ≤ k, then cv/e θr (G) = O(k log k). This means that for every r, the class Cθr has the vertex/edge Erdős-Pósa property. Using the combinatorial ideas from our proofs we introduce a unified approach for the design of an O(log OPT)-approximation algorithm for cv θr, pv θr, ce θr and pe θr that runs in O(n ・ log(n) ・ m) steps.
KW - Covering
KW - Erdős-Pósa properties
KW - Graph packing
KW - Minors
UR - http://www.scopus.com/inward/record.url?scp=84956626661&partnerID=8YFLogxK
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U2 - 10.1007/978-3-319-28684-6_11
DO - 10.1007/978-3-319-28684-6_11
M3 - Conference contribution
AN - SCOPUS:84956626661
SN - 9783319286839
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 122
EP - 132
BT - Approximation and Online Algorithms - 13th International Workshop, WAOA 2015, Revised Selected Papers
A2 - Skutella, Martin
A2 - Sanità, Laura
PB - Springer Verlag
T2 - 13th International Workshop on Approximation and Online Algorithms, WAOA 2015
Y2 - 17 September 2015 through 18 September 2015
ER -