{ "id": "2302.13098", "version": "v1", "published": "2023-02-25T15:06:31.000Z", "updated": "2023-02-25T15:06:31.000Z", "title": "Double semidirect products and skew left braces of size np", "authors": [ "Teresa Crespo", "Daniel Gil-Muñoz", "Anna Rio", "Montserrat Vela" ], "categories": [ "math.GR", "math.NT" ], "abstract": "We define the double semidirect product of skew left braces and prove that if $p$ is an odd prime and $n$ is an integer such that $p\\nmid n$ and each group of order $np$ has a unique $p$-Sylow subgroup, then any skew left brace of size $np$ is a double semidirect product of the trivial brace of size $p$ and a skew brace of size $n$. We develop an algorithm to obtain all braces of size $np$ from the set of braces of size $n$ and provide a formula to count them. We use the result to describe all braces of size $12p$ for $p\\ge 7$ and prove a conjecture of Bardakov, M.V. Neshchadim and M.K. Yadav.", "revisions": [ { "version": "v1", "updated": "2023-02-25T15:06:31.000Z" } ], "analyses": { "keywords": [ "skew left brace", "double semidirect product", "size np", "sylow subgroup", "odd prime" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }