Title
Arc‐Disjoint Directed and Undirected Cycles in Digraphs
Abstract
The dicycle transversal number t(D) of a digraph D is the minimum size of a dicycle transversal of D, that is a set of vertices of D, whose removal from D makes it acyclic. An arc a of a digraph D with at least one cycle is a transversal arc if a is in every directed cycle of D (making D - a acyclic). In [3] and [4], we completely characterized the complexity of following problem: Given a digraph D, decide if there is a dicycle B in D and a cycle C in its underlying undirected graph UG(D) such that V (B) boolean AND V (C) = empty set. It turns out that the problem is polynomially solvable for digraphs with a constantly bounded number of transversal vertices (including cases where tau(D) >= 2). In the remaining case (allowing arbitrarily many transversal vertices) the problem is NP-complete. In this article, we classify the complexity of the arc-analog of this problem, where we ask for a dicycle B and a cycle C that are arc-disjoint, but not necessarily vertex-disjoint. We prove that the problem is polynomially solvable for strong digraphs and for digraphs with a constantly bounded number of transversal arcs (but possibly an unbounded number of transversal vertices). In the remaining case (allowing arbitrarily many transversal arcs) the problem is NP-complete. (C) 2015 Wiley Periodicals, Inc.
Year
DOI
Venue
2016
10.1002/jgt.22006
JOURNAL OF GRAPH THEORY
Keywords
DocType
Volume
cycle,dicycle,disjoint cycle problem,arc-disjoint cycle problem,mixed problem,cycle transversal number,transversal arc
Journal
83.0
Issue
ISSN
Citations 
4.0
0364-9024
0
PageRank 
References 
Authors
0.34
6
4
Name
Order
Citations
PageRank
Jorgen Bang-Jensen113216.95
Matthias Kriesell234943.73
alessandro maddaloni300.34
Sven Simonsen492.09