{ "id": "1609.01370", "version": "v1", "published": "2016-09-06T02:05:20.000Z", "updated": "2016-09-06T02:05:20.000Z", "title": "The probability of avoiding consecutive patterns in the Mallows distribution", "authors": [ "Harry Crane", "Stephen DeSalvo", "Sergi Elizalde" ], "comment": "34 pages, 12 figures", "categories": [ "math.CO", "math.PR" ], "abstract": "We use various combinatorial and probabilistic techniques to study growth rates for the probability that a random permutation from the Mallows distribution avoids consecutive patterns. The Mallows distribution behaves like a $q$-analogue of the uniform distribution by weighting each permutation $\\pi$ by $q^{inv(\\pi)}$, where $inv(\\pi)$ is the number of inversions in $\\pi$ and $q$ is a positive, real-valued parameter. We prove that the growth rate exists for all patterns and all $q>0$, and we generalize Goulden and Jackson's cluster method to keep track of the number of inversions in permutations avoiding a given consecutive pattern. Using singularity analysis, we approximate the growth rates for length-3 patterns, monotone patterns, and non-overlapping patterns starting with 1, and we compare growth rates between different patterns. We also use Stein's method to show that, under certain assumptions on $q$, the length of $\\sigma$, and $inv(\\sigma)$, the number of occurrences of a given pattern $\\sigma$ is well approximated by the normal distribution.", "revisions": [ { "version": "v1", "updated": "2016-09-06T02:05:20.000Z" } ], "analyses": { "subjects": [ "05A05", "60C05", "05A15", "05A16", "62E17", "62E20", "05A30" ], "keywords": [ "avoiding consecutive patterns", "probability", "mallows distribution avoids consecutive patterns", "permutation", "mallows distribution behaves" ], "note": { "typesetting": "TeX", "pages": 34, "language": "en", "license": "arXiv", "status": "editable" } } }