{ "id": "1011.0357", "version": "v3", "published": "2010-11-01T15:50:09.000Z", "updated": "2011-10-15T17:46:24.000Z", "title": "Determination of the number of isomorphism classes of extensions of a $\\kp$-adic field", "authors": [ "Maurizio Monge" ], "comment": "5 pages", "categories": [ "math.NT", "math.CO", "math.GR" ], "abstract": "We deduce a formula enumerating the isomorphism classes of extensions of a $\\kp$-adic field $K$ with given ramification $e$ and inertia $f$. The formula follows from a simple group-theoretic lemma, plus the Krasner formula and an elementary class field theory computation. It shows that the number of classes only depends on the ramification and inertia of the extensions $K/\\Q_p$, and $K(\\zeta_{p^m})/K$ obtained adding the $p^m$-th roots of 1, for all $p^m$ dividing $e$.", "revisions": [ { "version": "v3", "updated": "2011-10-15T17:46:24.000Z" } ], "analyses": { "subjects": [ "11S15", "12B25", "05A19", "20D60" ], "keywords": [ "adic field", "isomorphism classes", "extensions", "elementary class field theory computation", "determination" ], "note": { "typesetting": "TeX", "pages": 5, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1011.0357M" } } }