{ "id": "0712.3895", "version": "v1", "published": "2007-12-23T05:29:02.000Z", "updated": "2007-12-23T05:29:02.000Z", "title": "An Enumeration of Graphical Designs", "authors": [ "Yeow Meng Chee", "Petteri Kaski" ], "comment": "16 pages", "journal": "Journal of Combinatorial Designs, vol. 16, no. 1, pp. 70-85, 2008", "doi": "10.1002/jcd.20137", "categories": [ "math.CO" ], "abstract": "Let $\\Psi(t,k)$ denote the set of pairs $(v,\\lambda)$ for which there exists a graphical $t$-$(v,k,\\lambda)$ design. Most results on graphical designs have gone to show the finiteness of $\\Psi(t,k)$ when $t$ and $k$ satisfy certain conditions. The exact determination of $\\Psi(t,k)$ for specified $t$ and $k$ is a hard problem and only $\\Psi(2,3)$, $\\Psi(2,4)$, $\\Psi(3,4)$, $\\Psi(4,5)$, and $\\Psi(5,6)$ have been determined. In this paper, we determine completely the sets $\\Psi(2,5)$ and $\\Psi(3,5)$. As a result, we find more than 270000 inequivalent graphical designs, and more than 8000 new parameter sets for which there exists a graphical design. Prior to this, graphical designs are known for only 574 parameter sets.", "revisions": [ { "version": "v1", "updated": "2007-12-23T05:29:02.000Z" } ], "analyses": { "keywords": [ "parameter sets", "enumeration", "hard problem", "inequivalent graphical designs", "exact determination" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0712.3895M" } } }