{ "id": "2010.02792", "version": "v1", "published": "2020-10-06T15:01:31.000Z", "updated": "2020-10-06T15:01:31.000Z", "title": "Optimal orientations of vertex-multiplications of cartesian products of graphs", "authors": [ "W. H. W. Wong", "E. G. Tay" ], "comment": "29 pages", "categories": [ "math.CO" ], "abstract": "Koh and Tay proved a fundamental classification of $G$ vertex-multiplications into three classes $\\mathscr{C}_0, \\mathscr{C}_1$ and $\\mathscr{C}_2$. In this paper, we prove that vertex-multiplications of cartesian products of graphs $G\\times H$ lie in $\\mathscr{C}_0$ ($\\mathscr{C}_0\\cup \\mathscr{C}_1$ resp.) if $G^{(2)}\\in \\mathscr{C}_0$ ($\\mathscr{C}_1$ resp.), $d(G)\\ge 2$ and $d(G\\times H)\\ge 4$. We also focus on cartesian products involving trees, paths and cycles and show that most of them lie in $\\mathscr{C}_0$.", "revisions": [ { "version": "v1", "updated": "2020-10-06T15:01:31.000Z" } ], "analyses": { "subjects": [ "05C12", "05C20", "05D05", "G.2.2", "F.2.2" ], "keywords": [ "cartesian products", "optimal orientations", "vertex-multiplications", "fundamental classification" ], "note": { "typesetting": "TeX", "pages": 29, "language": "en", "license": "arXiv", "status": "editable" } } }