Arc-disjoint spanning sub(di)graphs in digraphs

  • Authors:
  • Jørgen Bang-Jensen;Anders Yeo

  • Affiliations:
  • Department of Mathematics and Computer Science, University of Southern Denmark, Odense DK-5230, Denmark;Department of Computer Science, Royal Holloway, University of London, Egham Surrey TW20 0EX, United Kingdom

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2012

Quantified Score

Hi-index 5.23

Visualization

Abstract

We prove that a number of natural problems concerning the existence of arc-disjoint directed and ''undirected'' (spanning) subdigraphs in a digraph are NP-complete. Among these are the following of which the first settles an open problem due to Thomasse (see e.g. Bang-Jensen and Gutin (2009) [1, Problem 9.9.7] and Bang-Jensen and Kriesell (2009) [5,4]) and the second settles an open problem posed in Bang-Jensen and Kriesell (2009) [5]. *Given a directed graph D and a vertex s of D; does D contain an out-branching B"s^+ rooted at s such that the digraph remains connected (in the underlying sense) after removing all arcs of B"s^+? *Given a strongly connected directed graph D; does D contain a spanning strong subdigraph D^' such that the digraph remains connected (in the underlying sense) after removing all arcs of D^'?