{ "id": "1002.2054", "version": "v1", "published": "2010-02-10T10:05:18.000Z", "updated": "2010-02-10T10:05:18.000Z", "title": "The number of permutations with k inversions", "authors": [ "Gábor Hegedüs" ], "comment": "20 pages, submitted to J. of Int. Sequences", "categories": [ "math.CO", "math.AC" ], "abstract": "Let $n\\geq 1$, $0\\leq t\\leq {n \\choose 2}$ be arbitrary integers. Define the numbers $I_n(t)$ as the number of permutations of $[n]$ with $t$ inversions. Let $n,d\\geq 1$ and $0\\leq t\\leq (d-1)n$ be arbitrary integers. Define {\\em the polynomial coefficients} $H(n,d,t)$ as the numbers of compositions of $t$ with at most $n$ parts, no one of which is greater than $d-1$. In our article we give explicit formulas for the numbers $I_n(t)$ and $H(n,d,t)$ using the theory of Gr\\\"obner bases and free resolutions.", "revisions": [ { "version": "v1", "updated": "2010-02-10T10:05:18.000Z" } ], "analyses": { "subjects": [ "05A15", "13P10", "16E05" ], "keywords": [ "inversions", "permutations", "arbitrary integers", "polynomial coefficients", "explicit formulas" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1002.2054H" } } }