Acyclic Subgraphs of Planar Digraphs

An acyclic set in a digraph is a set of vertices that induces an acyclic subgraph. In 2011, Harutyunyan conjectured that every planar digraph on n vertices without directed 2-cycles possesses an acyclic set of size at least 3n=5. We prove this conjecture for digraphs where every directed cycle has l...

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Bibliographic Details
Main Authors: Golowich, Noah (Author), Rolnick, David S. (Contributor)
Other Authors: Massachusetts Institute of Technology. Department of Mathematics (Contributor)
Format: Article
Language:English
Published: European Mathematical Information Service (EMIS), 2015-09-08T18:58:24Z.
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Online Access:Get fulltext
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100 1 0 |a Golowich, Noah  |e author 
100 1 0 |a Massachusetts Institute of Technology. Department of Mathematics  |e contributor 
100 1 0 |a Rolnick, David S.  |e contributor 
700 1 0 |a Rolnick, David S.  |e author 
245 0 0 |a Acyclic Subgraphs of Planar Digraphs 
260 |b European Mathematical Information Service (EMIS),   |c 2015-09-08T18:58:24Z. 
856 |z Get fulltext  |u http://hdl.handle.net/1721.1/98410 
520 |a An acyclic set in a digraph is a set of vertices that induces an acyclic subgraph. In 2011, Harutyunyan conjectured that every planar digraph on n vertices without directed 2-cycles possesses an acyclic set of size at least 3n=5. We prove this conjecture for digraphs where every directed cycle has length at least 8. More generally, if g is the length of the shortest directed cycle, we show that there exists an acyclic set of size at least (1 - 3/g)n. 
546 |a en_US 
655 7 |a Article 
773 |t Electronic Journal of Combinatorics