{ "id": "1906.03730", "version": "v1", "published": "2019-06-09T22:44:47.000Z", "updated": "2019-06-09T22:44:47.000Z", "title": "Explicit methods for the Hasse norm principle and applications to $A_n$ and $S_n$ extensions", "authors": [ "André Macedo", "Rachel Newton" ], "comment": "40 pages, comments welcome!", "categories": [ "math.NT" ], "abstract": "Let $K/k$ be an extension of number fields. We describe theoretical results and computational methods for calculating the obstruction to the Hasse norm principle for $K/k$ and the defect of weak approximation for the norm one torus $R^1_{K/k} \\mathbb{G}_m$. We apply our techniques to give explicit and computable formulae for the obstruction to the Hasse norm principle and the defect of weak approximation when the normal closure of $K/k$ has symmetric or alternating Galois group.", "revisions": [ { "version": "v1", "updated": "2019-06-09T22:44:47.000Z" } ], "analyses": { "subjects": [ "14G05", "11E72", "11R37", "20G30" ], "keywords": [ "hasse norm principle", "explicit methods", "applications", "weak approximation", "number fields" ], "note": { "typesetting": "TeX", "pages": 40, "language": "en", "license": "arXiv", "status": "editable" } } }