Title
Vertex-disjoint directed and undirected cycles in general digraphs.
Abstract
The dicycle transversal number τ(D) of a digraph D is the minimum size of a dicycle transversal of D, i.e. a set T⊆V(D) such that D−T is acyclic. We study the 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)∩V(C)=∅. It is known that there is a polynomial time algorithm for this problem when restricted to strongly connected graphs, which actually finds B, C if they exist. We generalize this to any class of digraphs D with either τ(D)≠1 or τ(D)=1 and a bounded number of dicycle transversals, and show that the problem is NP-complete for a special class of digraphs D with τ(D)=1 and, hence, in general.
Year
DOI
Venue
2014
10.1016/j.jctb.2013.10.005
Journal of Combinatorial Theory, Series B
Keywords
Field
DocType
Cycle,Dicycle,Disjoint cycle problem,Mixed problem,Cycle transversal number,Intercyclic digraphs
Discrete mathematics,Combinatorics,Dicycle,Disjoint sets,Vertex (geometry),Transversal (geometry),Time complexity,Strongly connected component,Digraph,Mathematics,Bounded function
Journal
Volume
ISSN
Citations 
106
0095-8956
5
PageRank 
References 
Authors
0.61
4
4
Name
Order
Citations
PageRank
Jørgen Bang-Jensen157368.96
Matthias Kriesell234943.73
Alessandro Maddaloni3102.09
Sven Simonsen492.09