{ "id": "2011.01658", "version": "v1", "published": "2020-11-03T12:19:41.000Z", "updated": "2020-11-03T12:19:41.000Z", "title": "Numbers represented by restricted sums of four squares", "authors": [ "Guang-Liang Zhou", "Yue-Feng She" ], "comment": "18 pages", "categories": [ "math.NT" ], "abstract": "In this paper, we prove some results of restricted sums of four squares using arithmetic of quaternions in the ring of Lipschitz integers. For example, we show that every nonnegative integer $n$ can be written as $x^{2}+y^{2}+z^{2}+t^{2}$ where $x,y,z,t$ are integers and $x+y+2z+2t$ is a square or a cube.", "revisions": [ { "version": "v1", "updated": "2020-11-03T12:19:41.000Z" } ], "analyses": { "keywords": [ "restricted sums", "lipschitz integers", "quaternions" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable" } } }