{ "id": "2108.00822", "version": "v1", "published": "2021-07-16T15:23:47.000Z", "updated": "2021-07-16T15:23:47.000Z", "title": "Extremal product-one free sequences over $C_n \\rtimes_s C_2$", "authors": [ "Fabio Enrique Brochero Martínez", "Sávio Ribas" ], "comment": "9 pages. This is a complete answer to the inverse problem proposed in the old versions of the paper \"The $\\{1,s\\}$-weighted Davenport constant in $C_n^k$\". In those old versions, partial answers were given using the bounds of the weighted problem. This complete answer does not use any bound obtained there", "categories": [ "math.NT", "math.CO" ], "abstract": "Let $G$ be a finite group multiplicatively written. The small Davenport constant of $G$ is the maximum positive integer ${\\sf d}(G)$ such that there exists a sequence $S$ of length ${\\sf d}(G)$ for which every subsequence of $S$ is product-one free. Let $s^2 \\equiv 1 \\pmod n$, where $s \\not\\equiv \\pm1 \\pmod n$. It has been proven that ${\\sf d}(C_n \\rtimes_s C_2) = n$ (see Lemma 6 of [Zhuang, Gao; Europ. J. Combin. 26 (2005), 1053-1059]). In this paper, we determine all sequences over $C_n \\rtimes_s C_2$ of length $n$ which are product-one free. It completes the classification of all product-one free sequences over every group of the form $C_n \\rtimes_s C_2$, including the quasidihedral groups and the modular maximal-cyclic groups.", "revisions": [ { "version": "v1", "updated": "2021-07-16T15:23:47.000Z" } ], "analyses": { "subjects": [ "11P70", "11B50" ], "keywords": [ "extremal product-one free sequences", "modular maximal-cyclic groups", "finite group multiplicatively written", "small davenport constant", "quasidihedral groups" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }