Abstract
Answering a question of Adrian Bondy (Per. Comm.), we prove that every strong digraph has a spanning strong subgraph with at most n+2 α−2 arcs, where α is the size of a maximum stable set of D. Such a spanning subgraph can be found in polynomial time. An infinite family of oriented graphs for which this bound is sharp was given by Odile Favaron (Discrete Math. 146 (1995) 289). A direct corollary of our result is that there exists 2 α−1 directed cycles which span D. Tibor Gallai (Theory of Graphs and its Applications, Czech. Acad. Sci. Prague, 1964, p. 161) conjectured that α directed cycles would be enough.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
