Cookies?
Library Header Image
LSE Research Online LSE Library Services

Transversals of subtree hypergraphs and the source location problem in digraphs

van den Heuvel, Jan ORCID: 0000-0003-0897-9148 and Johnson, Matthew (2008) Transversals of subtree hypergraphs and the source location problem in digraphs. Networks, 51 (2). pp. 113-119. ISSN 0028-3045

Full text not available from this repository.
Identification Number: 10.1002/net.20206

Abstract

A hypergraph H = (V,E) is a subtree hypergraph if there is a tree T on V such that each hyperedge of E induces a subtree of T. Since the number of edges of a subtree hypergraph can be exponential in n = |V|, one can not always expect to be able to find a minimum size transversal in time polynomial in n. In this paper, we show that if it is possible to decide if a set of vertices W V is a transversal in time S(n) (where n = |V|), then it is possible to find a minimum size transversal in O(n3S(n)). This result provides a polynomial algorithm for the Source Location Problem: a set of (k,l)-sources for a digraph D = (V,A) is a subset S of V such that for any v V there are k arc-disjoint paths that each join a vertex of S to v and l arc-disjoint paths that each join v to S. The Source Location Problem is to find a minimum size set of (k,l)-sources. We show that this is a case of finding a transversal of a subtree hypergraph, and that in this case S(n) is polynomial.

Item Type: Article
Official URL: http://www3.interscience.wiley.com/journal/32046/h...
Additional Information: © 2008 Wiley-Blackwell
Divisions: Mathematics
Subjects: Q Science > QA Mathematics
Date Deposited: 18 Feb 2009 12:35
Last Modified: 13 Sep 2024 22:25
URI: http://eprints.lse.ac.uk/id/eprint/22725

Actions (login required)

View Item View Item