{ "id": "2010.06273", "version": "v1", "published": "2020-10-13T10:32:09.000Z", "updated": "2020-10-13T10:32:09.000Z", "title": "The feasible regions for consecutive patterns of pattern-avoiding permutations", "authors": [ "Jacopo Borga", "Raul Penaguiao" ], "categories": [ "math.CO", "math.PR" ], "abstract": "We study the feasible region for consecutive patterns of pattern-avoiding permutations. More precisely, given a family $\\mathcal C$ of permutations avoiding a fixed set of patterns, we study the limit of proportions of consecutive patterns on large permutations of $\\mathcal C$. These limits form a region, which we call the \\emph{pattern-avoiding feasible region for $\\mathcal C$}. We show that, when $\\mathcal C$ is the family of $\\tau$-avoiding permutations, with either $\\tau$ of size three or $\\tau$ a monotone pattern, the pattern-avoiding feasible region for $\\mathcal C$ is a polytope. We also determine its dimension using a new tool for the monotone pattern case whereby we are able to compute the dimension of the image of a polytope after a projection. We further show some general results for the pattern-avoiding feasible region for any family $\\mathcal C$ of permutations avoiding a fixed set of patterns, and we conjecture a general formula for its dimension. Along the way, we discuss connections of this work with the problem of packing patterns in pattern-avoiding permutations and to the study of local limits for pattern-avoiding permutations.", "revisions": [ { "version": "v1", "updated": "2020-10-13T10:32:09.000Z" } ], "analyses": { "keywords": [ "pattern-avoiding permutations", "consecutive patterns", "pattern-avoiding feasible region", "fixed set", "general formula" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }