{ "id": "1910.02753", "version": "v1", "published": "2019-10-07T12:35:44.000Z", "updated": "2019-10-07T12:35:44.000Z", "title": "Enumerating extensions of mutually orthogonal Latin squares", "authors": [ "Simona Boyadzhiyska", "Shagnik Das", "Tibor Szabó" ], "comment": "18 pages", "categories": [ "math.CO" ], "abstract": "Two $n \\times n$ Latin squares $L_1, L_2$ are said to be orthogonal if, for every ordered pair $(x,y)$ of symbols, there are coordinates $(i,j)$ such that $L_1(i,j) = x$ and $L_2(i,j) = y$. A $k$-MOLS is a sequence of $k$ pairwise-orthogonal Latin squares, and the existence and enumeration of these objects has attracted a great deal of attention. Recent work of Keevash and Luria provides, for all fixed $k$, log-asymptotically tight bounds on the number of $k$-MOLS. To study the situation when $k$ grows with $n$, we bound the number of ways a $k$-MOLS can be extended to a $(k+1)$-MOLS. These bounds are again tight for constant $k$, and allow us to deduce upper bounds on the total number of $k$-MOLS for all $k$. These bounds are close to tight even for $k$ linear in $n$, and readily generalize to the broader class of gerechte designs, which include Sudoku squares.", "revisions": [ { "version": "v1", "updated": "2019-10-07T12:35:44.000Z" } ], "analyses": { "subjects": [ "05B15" ], "keywords": [ "mutually orthogonal latin squares", "enumerating extensions", "deduce upper bounds", "pairwise-orthogonal latin squares", "broader class" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable" } } }