{ "id": "2207.01215", "version": "v1", "published": "2022-07-04T05:55:43.000Z", "updated": "2022-07-04T05:55:43.000Z", "title": "Derangements in wreath products of permutation groups", "authors": [ "Vishnuram Arumugam", "Heiko Dietrich", "S. P. Glasby" ], "comment": "14 pages", "categories": [ "math.GR", "math.CO" ], "abstract": "Given a finite group $G$ acting on a set $X$ let $\\delta_k(G,X)$ denote the proportion of elements in $G$ that have exactly $k$ fixed points in $X$. Let $\\mathrm{S}_n$ denote the symmetric group acting on $[n]=\\{1,2,\\dots,n\\}$. For $A\\le\\mathrm{S}_m$ and $B\\le\\mathrm{S}_n$, the permutational wreath product $A\\wr B$ has two natural actions and we give formulas for both, $\\delta_k(A\\wr B,[m]{\\times}[n])$ and $\\delta_k(A\\wr B,[m]^{[n]})$. We prove that for $k=0$ the values of these proportions are dense in the intervals $[\\delta_0(B,[n]),1]$ and $[\\delta_0(A,[m]),1]$. Among further result, we provide estimates for $\\delta_0(G,[m]^{[n]})$ for subgroups $G\\leq \\mathrm{S}_m\\wr\\mathrm{S}_n$ containing $\\mathrm{A}_m^{[n]}$.", "revisions": [ { "version": "v1", "updated": "2022-07-04T05:55:43.000Z" } ], "analyses": { "subjects": [ "20B07", "20B35", "05A05" ], "keywords": [ "permutation groups", "derangements", "permutational wreath product", "natural actions", "proportion" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }