{ "id": "1705.03671", "version": "v1", "published": "2017-05-10T09:34:42.000Z", "updated": "2017-05-10T09:34:42.000Z", "title": "Arity of universal quadratic forms over real quadratic fields", "authors": [ "Valentin Blomer", "Vítězslav Kala" ], "comment": "17 pages", "categories": [ "math.NT" ], "abstract": "We study the minimal number of variables required by a totally positive definite diagonal universal quadratic form over a real quadratic field $\\mathbb Q(\\sqrt D)$ and obtain lower and upper bounds for it in terms of certain sums of coefficients of the associated continued fraction. We also estimate such sums in terms of $D$.", "revisions": [ { "version": "v1", "updated": "2017-05-10T09:34:42.000Z" } ], "analyses": { "subjects": [ "11E12", "11R11", "11A55" ], "keywords": [ "real quadratic field", "definite diagonal universal quadratic form", "positive definite diagonal universal quadratic", "totally positive definite diagonal universal" ], "note": { "typesetting": "TeX", "pages": 17, "language": "en", "license": "arXiv", "status": "editable" } } }