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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Detalhes bibliográficos
Principais autores: Golowich, Noah, Rolnick, David S.
Outros Autores: Massachusetts Institute of Technology. Department of Mathematics
Formato: Artigo
Idioma:en_US
Publicado em: European Mathematical Information Service (EMIS) 2015
Acesso em linha:http://hdl.handle.net/1721.1/98410
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author Golowich, Noah
Rolnick, David S.
author2 Massachusetts Institute of Technology. Department of Mathematics
author_facet Massachusetts Institute of Technology. Department of Mathematics
Golowich, Noah
Rolnick, David S.
author_sort Golowich, Noah
collection MIT
description 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.
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spelling mit-1721.1/984102022-10-01T10:50:27Z Acyclic Subgraphs of Planar Digraphs Golowich, Noah Rolnick, David S. Massachusetts Institute of Technology. Department of Mathematics Rolnick, David S. 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. 2015-09-08T18:58:24Z 2015-09-08T18:58:24Z 2015-07 2014-08 Article http://purl.org/eprint/type/JournalArticle 1077-8926 http://hdl.handle.net/1721.1/98410 Golowich, Noah, and David Rolnick. "Acyclic Subgraphs of Planar Digraphs." The Electronic Journal of Combinatorics 22(3) (2015), #P3.7. en_US http://www.combinatorics.org/ojs/index.php/eljc/article/view/v22i3p7/pdf Electronic Journal of Combinatorics Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf European Mathematical Information Service (EMIS) European Mathematical Information Service (EMIS)
spellingShingle Golowich, Noah
Rolnick, David S.
Acyclic Subgraphs of Planar Digraphs
title Acyclic Subgraphs of Planar Digraphs
title_full Acyclic Subgraphs of Planar Digraphs
title_fullStr Acyclic Subgraphs of Planar Digraphs
title_full_unstemmed Acyclic Subgraphs of Planar Digraphs
title_short Acyclic Subgraphs of Planar Digraphs
title_sort acyclic subgraphs of planar digraphs
url http://hdl.handle.net/1721.1/98410
work_keys_str_mv AT golowichnoah acyclicsubgraphsofplanardigraphs
AT rolnickdavids acyclicsubgraphsofplanardigraphs