{ "id": "2203.12397", "version": "v1", "published": "2022-03-23T13:17:56.000Z", "updated": "2022-03-23T13:17:56.000Z", "title": "On independent domination in direct products", "authors": [ "Kirsti Kuenzel", "Douglas F. Rall" ], "comment": "14 pages, 2 figures, 2 tables", "categories": [ "math.CO" ], "abstract": "In \\cite{nr-1996} Nowakowski and Rall listed a series of conjectures involving several different graph products. In particular, they conjectured that $i(G\\times H) \\ge i(G)i(H)$ where $i(G)$ is the independent domination number of $G$ and $G\\times H$ is the direct product of graphs $G$ and $H$. We show this conjecture is false, and, in fact, construct pairs of graphs for which $\\min\\{i(G), i(H)\\} - i(G\\times H)$ is arbitrarily large. We also give the exact value of $i(G\\times K_n)$ when $G$ is either a path or a cycle.", "revisions": [ { "version": "v1", "updated": "2022-03-23T13:17:56.000Z" } ], "analyses": { "subjects": [ "05C69", "05C76" ], "keywords": [ "direct product", "independent domination number", "graph products", "conjecture", "construct pairs" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }