{ "id": "1306.5708", "version": "v3", "published": "2013-06-24T18:53:56.000Z", "updated": "2014-08-18T23:51:55.000Z", "title": "Blocks in cycles and k-commuting permutations", "authors": [ "Rutilo Moreno", "Luis Manuel Rivera" ], "comment": "25 pages. v3 is a major revision", "categories": [ "math.CO" ], "abstract": "Let $k$ be a nonnegative integer, and let $\\alpha$ and $\\beta$ be two permutations of $n$ symbols. We say that $\\alpha$ and $\\beta$ $k$-commute if $H(\\alpha\\beta, \\beta\\alpha)=k$, where $H$ denotes the Hamming metric between permutations. In this paper, we consider the problem of finding the permutations that $k$-commute with a given permutation. Our main result is a characterization of permutations that $k$-commute with a given permutation $\\beta$ in terms of blocks in cycles in the decomposition of $\\beta$ as a product of disjoint cycles. Using this characterization, we provide formulas for the number of permutations that $k$-commute with a transposition, a fixed-point free involution and an $n$-cycle, for any $k$. Also, we determine the number of permutations that $k$-commute with any given permutation, for $k \\leq 4$.", "revisions": [ { "version": "v3", "updated": "2014-08-18T23:51:55.000Z" } ], "analyses": { "subjects": [ "05A05", "05A15", "20B30" ], "keywords": [ "k-commuting permutations", "fixed-point free involution", "disjoint cycles", "main result", "characterization" ], "note": { "typesetting": "TeX", "pages": 25, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1306.5708M" } } }