{ "id": "1107.4595", "version": "v4", "published": "2011-07-22T19:04:24.000Z", "updated": "2014-05-19T08:36:45.000Z", "title": "The order of the reductions of an algebraic integer", "authors": [ "Antonella Perucca" ], "comment": "revised and rewritten; new tables of examples checked with sage; the revisions include the referee's comments", "categories": [ "math.NT" ], "abstract": "Let K be a number field, and let a be a non-zero element of K. Fix some prime number l. We compute the density of the following set: the primes p of K such that the multiplicative order of the reduction of a modulo p is coprime to l (or, more generally, has some prescribed l-adic valuation). We evaluate the degree over K of extensions of the form K(\\zeta_m, \\sqrt[n]{a}) with n\\leq m, which are obtained by adjoining a root of unity of order l^m and the l^n-th roots of a, as this is needed for computing the above density.", "revisions": [ { "version": "v4", "updated": "2014-05-19T08:36:45.000Z" } ], "analyses": { "subjects": [ "11R44", "11R18", "11Y40" ], "keywords": [ "algebraic integer", "non-zero element", "number field", "prescribed l-adic valuation", "prime number" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1107.4595P" } } }