DMTCS Proceedings, 2005 European Conference on Combinatorics, Graph Theory and Applications (EuroComb '05)

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DMTCS Conference vol AE (2005), pp. 45-50

DMTCS

2005 European Conference on Combinatorics, Graph Theory and Applications (EuroComb '05)

Stefan Felsner (ed.)

DMTCS Conference Volume AE (2005), pp. 45-50


author: Bruce Reed and David R. Wood
title: Fast separation in a graph with an excluded minor
keywords: graph algorithm, separator, minor
abstract: Let
G
be an
n
-vertex
m
-edge graph with weighted vertices. A pair of vertex sets
A,B⊆V(G)
is a 2/3-separation of order
|A∩B|
if
A ∪B = V(G)
, there is no edge between
A \ B
and
B \ A
, and both
A \ B
and
B \ A
have weight at most
2/3
the total weight of
G
. Let
ℓ∈ℤ+
be fixed. Alon, Seymour and Thomas [J. Amer. Math. Soc. 1990] presented an algorithm that in
O
(n
1/2
m)
time, either outputs a
K
-minor of
G
, or a separation of
G
of order
O
(n
1/2
)
. Whether there is a
O
(n+m)
time algorithm for this theorem was left as open problem. In this paper, we obtain a
O
(n+m)
time algorithm at the expense of
O
(n
2/3
)
separator. Moreover, our algorithm exhibits a tradeoff between running time and the order of the separator. In particular, for any given
ε∈[0,1/2]
, our algorithm either outputs a
K
-minor of
G
, or a separation of
G
with order
O
(n
(2-ε)/3
)
in
O
(n
1+ε
+m)
time.
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reference: Bruce Reed and David R. Wood (2005), Fast separation in a graph with an excluded minor , in 2005 European Conference on Combinatorics, Graph Theory and Applications (EuroComb '05), Stefan Felsner (ed.), Discrete Mathematics and Theoretical Computer Science Proceedings AE, pp. 45-50
bibtex: For a corresponding BibTeX entry, please consider our BibTeX-file.
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