{ "id": "1605.06577", "version": "v1", "published": "2016-05-21T02:50:35.000Z", "updated": "2016-05-21T02:50:35.000Z", "title": "Avoiding patterns in matrices via a small number of changes", "authors": [ "Maria Axenovich", "Ryan Martin" ], "comment": "6 pages", "journal": "SIAM J. Discrete Math., 20(1) (2006), 49--54", "doi": "10.1137/S0895480104445150", "categories": [ "math.CO" ], "abstract": "Let ${\\cal A}=\\{A_1,\\ldots, A_r\\}$ be a partition of a set $\\{1,\\ldots,m\\}\\times\\{1,\\ldots, n\\}$ into $r$ nonempty subsets, and $A=(a_{ij})$ be an $m\\times n$ matrix. We say that $A$ has a pattern ${\\cal A}$ provided that $a_{ij}=a_{i'j'}$ if and only if $(i,j),(i',j')\\in A_t$ for some $t\\in\\{1,\\ldots,r\\}$. In this note we study the following function $f$ defined on the set of all $m\\times n$ matrices $M$ with $s$ distinct entries: $f(M; {\\cal A})$ is the smallest number of positions where the entries of $M$ need to be changed such that the resulting matrix does not have any submatrix with pattern ${\\cal A}$. We give an asymptotically tight value for $$ f(m,n; s, {\\cal A}) = \\max\\{f(M; {\\cal A}): M \\mbox{ is an } m\\times n\\mbox{ matrix with at most } s \\mbox{ distinct entries}\\} . $$", "revisions": [ { "version": "v1", "updated": "2016-05-21T02:50:35.000Z" } ], "analyses": { "subjects": [ "05A18", "05C50", "15A99" ], "keywords": [ "small number", "avoiding patterns", "nonempty subsets", "distinct entries", "smallest number" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 6, "language": "en", "license": "arXiv", "status": "editable" } } }