{ "id": "2106.12019", "version": "v1", "published": "2021-06-22T18:56:31.000Z", "updated": "2021-06-22T18:56:31.000Z", "title": "Length-Preserving Directions and Some Diophantine Equations", "authors": [ "Juan Tolosa" ], "comment": "5 figures", "journal": "American Mathematical Monthly 128:2, 125-139, February 2021", "doi": "10.1080/00029890", "categories": [ "math.NT", "math.SP" ], "abstract": "We study directions along which the norms of vectors are preserved under a linear map. In particular, we find families of matrices for which these directions are determined by integer vectors. We consider the two-dimensional case in detail, and also discuss the extension to the three-dimensional case.", "revisions": [ { "version": "v1", "updated": "2021-06-22T18:56:31.000Z" } ], "analyses": { "subjects": [ "15A18", "11D09", "15A06" ], "keywords": [ "diophantine equations", "length-preserving directions", "linear map", "study directions", "two-dimensional case" ], "tags": [ "journal article" ], "publication": { "publisher": "Taylor-Francis" }, "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }