{ "id": "1703.07672", "version": "v1", "published": "2017-03-22T14:25:58.000Z", "updated": "2017-03-22T14:25:58.000Z", "title": "Convergents as approximants in continued fraction expansions of complex numbers with Eisenstein integers", "authors": [ "S. G. Dani" ], "comment": "6 pages", "categories": [ "math.NT" ], "abstract": "Let $\\frak E$ denote be the ring of Eisenstein integers. Let $z\\in \\mathbb C$ and $p_n,q_n \\in \\frak E$ be such that $\\{p_n/q_n\\}$ is the sequence of convergents corresponding to the continued fraction expansion of $z$ with respect to the nearest integer algorithm. Then we show that for any $q\\in \\frak E$ such that $1\\leq |q|\\leq |q_n|$ and any $p\\in \\frak E$, $|qz-p|\\geq \\frac12 |q_nz-p_n|$. This enables us to conclude that $z\\in \\mathbb C$ is badly approximable, in terms of Eisenstein integers, if and only if the corresponding sequence of partial quotients is bounded.", "revisions": [ { "version": "v1", "updated": "2017-03-22T14:25:58.000Z" } ], "analyses": { "keywords": [ "continued fraction expansion", "eisenstein integers", "complex numbers", "convergents", "approximants" ], "note": { "typesetting": "TeX", "pages": 6, "language": "en", "license": "arXiv", "status": "editable" } } }