{ "id": "1907.07141", "version": "v1", "published": "2019-07-13T01:46:20.000Z", "updated": "2019-07-13T01:46:20.000Z", "title": "Variable degeneracy on toroidal graphs", "authors": [ "Rui Li", "Tao Wang" ], "comment": "10 pages, 5 figures. arXiv admin note: text overlap with arXiv:1803.01197", "categories": [ "math.CO", "cs.DM" ], "abstract": "Let $f$ be a nonnegative integer valued function on the vertex-set of a graph. A graph is {\\bf strictly $f$-degenerate} if each nonempty subgraph $\\Gamma$ has a vertex $v$ such that $\\deg_{\\Gamma}(v) < f(v)$. A {\\bf cover} of a graph $G$ is a graph $H$ with vertex set $V(H) = \\bigcup_{v \\in V(G)} L_{v}$, where $L_{v} = \\{\\,(v, 1), (v, 2), \\dots, (v, \\kappa)\\,\\}$; the edge set $\\mathscr{M} = \\bigcup_{uv \\in E(G)}\\mathscr{M}_{uv}$, where $\\mathscr{M}_{uv}$ is a matching between $L_{u}$ and $L_{v}$. A vertex set $R \\subseteq V(H)$ is a {\\bf transversal} of $H$ if $|R \\cap L_{v}| = 1$ for each $v \\in V(G)$. A transversal $R$ is a {\\bf strictly $f$-degenerate transversal} if $H[R]$ is strictly $f$-degenerate. In this paper, we give some structural results on planar and toroidal graphs with forbidden configurations, and give some sufficient conditions for the existence of strictly $f$-degenerate transversal by using these structural results.", "revisions": [ { "version": "v1", "updated": "2019-07-13T01:46:20.000Z" } ], "analyses": { "subjects": [ "05C15" ], "keywords": [ "toroidal graphs", "variable degeneracy", "degenerate transversal", "structural results", "vertex set" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }