{ "id": "1405.5762", "version": "v2", "published": "2014-05-22T14:06:59.000Z", "updated": "2014-05-29T11:57:16.000Z", "title": "Badly approximable numbers for sequences of balls", "authors": [ "Simon Baker" ], "comment": "7 pages. After completing this paper the author was made aware of a result due to Cassels. We now know that the work done in this paper is in fact a reasonably straightforward consequence of this result", "categories": [ "math.NT", "math.CA", "math.DS" ], "abstract": "It is a classical result from Diophantine approximation that the set of badly approximable numbers has Lebesgue measure zero. In this paper we generalise this result to more general sequences of balls. Given a countable set of closed $d$-dimensional Euclidean balls $\\{B(x_{i},r_{i})\\}_{i=1}^{\\infty},$ we say that $\\alpha\\in \\mathbb{R}^{d}$ is a badly approximable number with respect to $\\{B(x_{i},r_{i})\\}_{i=1}^{\\infty}$ if there exists $\\kappa(\\alpha)>0$ and $N(\\alpha)\\in\\mathbb{N}$ such that $\\alpha\\notin B(x_{i},\\kappa(\\alpha)r_{i})$ for all $i\\geq N(\\alpha)$. Under natural conditions on the set of balls, we prove that the set of badly approximable numbers with respect to $\\{B(x_{i},r_{i})\\}_{i=1}^{\\infty}$ has Lebesgue measure zero. Moreover, our approach yields a new proof that the set of badly approximable numbers has Lebesgue measure zero.", "revisions": [ { "version": "v2", "updated": "2014-05-29T11:57:16.000Z" } ], "analyses": { "subjects": [ "11K60", "28A80" ], "keywords": [ "badly approximable number", "lebesgue measure zero", "dimensional euclidean balls", "general sequences", "diophantine approximation" ], "note": { "typesetting": "TeX", "pages": 7, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1405.5762B" } } }