{ "id": "1706.03682", "version": "v1", "published": "2017-06-12T15:21:30.000Z", "updated": "2017-06-12T15:21:30.000Z", "title": "Two inequalities related to Vizing's conjecture", "authors": [ "Shira Zerbib" ], "categories": [ "math.CO" ], "abstract": "A well-known conjecture of Vizing is that $\\gamma(G \\square H) \\ge \\gamma(G)\\gamma(H)$ for any pair of graphs $G, H$, where $\\gamma$ is the domination number and $G \\square H$ is the Cartesian product of $G$ and $H$. Suen and Tarr, improving a result of Clark and Suen, showed $\\gamma(G \\square H) \\ge \\frac{1}{2}\\gamma(G)\\gamma(H) + \\frac{1}{2}\\min(\\gamma(G),\\gamma(H))$. We further improve their result by showing $\\gamma(G \\square H) \\ge \\frac{1}{2}\\gamma(G)\\gamma(H) + \\frac{1}{2}\\max(\\gamma(G),\\gamma(H)).$ We also prove a fractional version of Vizing's conjecture: $\\gamma(G \\square H) \\ge \\gamma(G)\\gamma^*(H)$.", "revisions": [ { "version": "v1", "updated": "2017-06-12T15:21:30.000Z" } ], "analyses": { "keywords": [ "vizings conjecture", "inequalities", "well-known conjecture", "domination number", "cartesian product" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }