{ "id": "2302.05165", "version": "v1", "published": "2023-02-10T10:45:33.000Z", "updated": "2023-02-10T10:45:33.000Z", "title": "The distribution of the multiplicative index of algebraic numbers over residue classes", "authors": [ "Pieter Moree", "Antonella Perucca", "Pietro Sgobba" ], "comment": "15 pages, comments are welcome", "categories": [ "math.NT" ], "abstract": "Let $K$ be a number field and $G$ a finitely generated torsion-free subgroup of $K^\\times$. Given a prime $\\mathfrak p$ of $K$ we denote by ${\\rm ind}_{\\mathfrak p}(G)$ the index of the subgroup $(G\\bmod\\mathfrak p)$ of the multiplicative group of the residue field at $\\mathfrak p$. Under the Generalized Riemann Hypothesis we determine the natural density of primes of $K$ for which this index is in a prescribed set $S$ and has prescribed Frobenius in a finite Galois extension $F$ of $K$. We study in detail the natural density in case $S$ is an arithmetic progression, in particular its positivity.", "revisions": [ { "version": "v1", "updated": "2023-02-10T10:45:33.000Z" } ], "analyses": { "subjects": [ "11R45", "11A07", "11R44" ], "keywords": [ "algebraic numbers", "residue classes", "multiplicative index", "distribution", "natural density" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable" } } }