{ "id": "1009.4471", "version": "v1", "published": "2010-09-22T20:24:06.000Z", "updated": "2010-09-22T20:24:06.000Z", "title": "Boxicity of Line Graphs", "authors": [ "L. Sunil Chandran", "Rogers Mathew", "Naveen Sivadasan" ], "comment": "14 pages", "categories": [ "math.CO", "cs.DM" ], "abstract": "Boxicity of a graph H, denoted by box(H), is the minimum integer k such that H is an intersection graph of axis-parallel k-dimensional boxes in R^k. In this paper, we show that for a line graph G of a multigraph, box(G) <= 2\\Delta(\\lceil log_2(log_2(\\Delta)) \\rceil + 3) + 1, where \\Delta denotes the maximum degree of G. Since \\Delta <= 2(\\chi - 1), for any line graph G with chromatic number \\chi, box(G) = O(\\chi log_2(log_2(\\chi))). For the d-dimensional hypercube H_d, we prove that box(H_d) >= (\\lceil log_2(log_2(d)) \\rceil + 1)/2. The question of finding a non-trivial lower bound for box(H_d) was left open by Chandran and Sivadasan in [L. Sunil Chandran and Naveen Sivadasan. The cubicity of Hypercube Graphs. Discrete Mathematics, 308(23):5795-5800, 2008]. The above results are consequences of bounds that we obtain for the boxicity of fully subdivided graphs (a graph which can be obtained by subdividing every edge of a graph exactly once).", "revisions": [ { "version": "v1", "updated": "2010-09-22T20:24:06.000Z" } ], "analyses": { "keywords": [ "line graph", "non-trivial lower bound", "axis-parallel k-dimensional boxes", "intersection graph", "minimum integer" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1009.4471C" } } }