{ "id": "2108.07984", "version": "v1", "published": "2021-08-18T05:57:59.000Z", "updated": "2021-08-18T05:57:59.000Z", "title": "Bounding the edge cover of a hypergraph", "authors": [ "Farhad Shahrokhi" ], "categories": [ "math.CO" ], "abstract": "Let $H=(V,E)$ be a hypergraph. Let $C\\subseteq E$, then $C$ is an {\\it edge cover}, or a {\\it set cover}, if $\\cup_{e\\in C} \\{v|v\\in e\\}=V$. A subset of vertices $X$ is {\\it independent} in $H,$ if no two vertices in $X$ are in any edge. Let $c(H)$ and $\\alpha(H)$ denote the cardinalities of a smallest edge cover and largest independent set in $H$, respectively. We show that $c(H)\\le {\\hat m}(h)c(H)$, where ${\\hat m}(H)$ is a parameter called the {\\it mighty degeneracy} of $H$. Furthermore, we show that the inequality is tight and demonstrate the applications in domination theory.", "revisions": [ { "version": "v1", "updated": "2021-08-18T05:57:59.000Z" } ], "analyses": { "keywords": [ "hypergraph", "smallest edge cover", "largest independent set", "set cover", "mighty degeneracy" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }