{ "id": "1909.04199", "version": "v1", "published": "2019-09-09T23:59:29.000Z", "updated": "2019-09-09T23:59:29.000Z", "title": "Further Results on the Pseudo-$L_{g}(s)$ Association Scheme with $g\\geq 3$, $s\\geq g+2$", "authors": [ "Congwei Wang", "Shanqi Pang", "Guangzhou Chen" ], "categories": [ "math.CO" ], "abstract": "It is inevitable that the $L_{g}(s)$ association scheme with $g\\geq 3, s\\geq g+2$ is a pseudo-$L_{g}(s)$ association scheme. On the contrary, although $s^2$ treatments of the pseudo-$L_{g}(s)$ association scheme can form one $L_{g}(s)$ association scheme, it is not always an $L_{g}(s)$ association scheme. Mainly because the set of cardinality $s$, which contains two first-associates treatments of the pseudo-$L_{g}(s)$ association scheme, is non-unique. Whether the order $s$ of a Latin square $\\mathbf{L}$ is a prime power or not, the paper proposes two new conditions in order to extend a $POL(s,w)$ containing $\\mathbf{L}$. It has been known that a $POL(s,w)$ can be extended to a $POL(s,s-1)$ so long as Bruck's \\cite{brh} condition $s\\geq \\frac{(s-1-w)^4-2(s-1-w)^3+2(s-1-w)^2+(s-1-w)}{2}$ is satisfied, Bruck's condition will be completely improved through utilizing six properties of the $L_{w+2}(s)$ association scheme in this paper. Several examples are given to elucidate the application of our results.", "revisions": [ { "version": "v1", "updated": "2019-09-09T23:59:29.000Z" } ], "analyses": { "subjects": [ "05B15" ], "keywords": [ "association scheme", "latin square", "prime power", "brucks condition", "first-associates treatments" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }