Disjoint paths in arborescences
نویسندگان
چکیده
منابع مشابه
Disjoint paths in arborescences
An arborescence in a digraph is a tree directed away from its root. A classical theorem of Edmonds characterizes which digraphs have λ arc-disjoint arborescences rooted at r. A similar theorem of Menger guarantees λ strongly arc disjoint rv-paths for every vertex v, where “strongly” means no two paths contain a pair of symmetric arcs. We prove that if a directed graph D contains two arc-disjoin...
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Given k pairs of vertices (si, ti) (1 ≤ i ≤ k) of a digraph G, how can we test whether there exist k vertex-disjoint directed paths from si to ti for 1 ≤ i ≤ k? This is NP-complete in general digraphs, even for k = 2 [2], but for k = 2 there is a polynomial-time algorithm when G is a tournament (or more generally, a semicomplete digraph), due to Bang-Jensen and Thomassen [1]. Here we prove that...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2005
ISSN: 0012-365X
DOI: 10.1016/j.disc.2004.12.005