{ "id": "1012.1231", "version": "v2", "published": "2010-12-06T16:37:30.000Z", "updated": "2011-02-22T02:38:23.000Z", "title": "A sufficient condition for the existence of an anti-directed 2-factor in a directed graph", "authors": [ "Ajit A. Diwan", "Josh B. Frye", "Michael J. Plantholt", "Shailesh K. Tipnis" ], "categories": [ "math.CO" ], "abstract": "Let D be a directed graph with vertex set V and order n. An anti-directed hamiltonian cycle H in D is a hamiltonian cycle in the graph underlying D such that no pair of consecutive arcs in H form a directed path in D. An anti-directed 2-factor in D is a vertex-disjoint collection of anti-directed cycles in D that span V. It was proved in [3] that if the indegree and the outdegree of each vertex of D is greater than (9/16)n then D contains an anti-directed hamilton cycle. In this paper we prove that given a directed graph D, the problem of determining whether D has an anti-directed 2-factor is NP-complete, and we use a proof technique similar to the one used in [3] to prove that if the indegree and the outdegree of each vertex of D is greater than (24/46)n then D contains an anti-directed 2-factor.", "revisions": [ { "version": "v2", "updated": "2011-02-22T02:38:23.000Z" } ], "analyses": { "subjects": [ "05C20", "05C45" ], "keywords": [ "directed graph", "sufficient condition", "proof technique similar", "vertex-disjoint collection", "anti-directed hamiltonian cycle" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1012.1231D" } } }