{ "id": "1305.6195", "version": "v2", "published": "2013-05-27T12:32:29.000Z", "updated": "2013-10-03T18:02:36.000Z", "title": "Maximum 4-degenerate subgraph of a planar graph", "authors": [ "Robert Lukoťka", "Ján Mazák", "Xuding Zhu" ], "categories": [ "math.CO", "cs.DM" ], "abstract": "A graph $G$ is $k$-degenerate if it can be transformed into an empty graph by subsequent removals of vertices of degree $k$ or less. We prove that every connected planar graph with average degree $d \\ge 2$ has a 4-degenerate induced subgraph containing at least $(38-d)/36$ of its vertices. This shows that every planar graph of order $n$ has a 4-degenerate induced subgraph of order more than $8/9 \\cdot n$. We also consider a local variation of this problem and show that in every planar graph with at least 7 vertices, deleting a suitable vertex allows us to subsequently remove at least 6 more vertices of degree four or less.", "revisions": [ { "version": "v2", "updated": "2013-10-03T18:02:36.000Z" } ], "analyses": { "keywords": [ "induced subgraph", "subsequent removals", "connected planar graph", "average degree", "empty graph" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1305.6195L" } } }