{ "id": "1211.4541", "version": "v1", "published": "2012-11-19T19:31:53.000Z", "updated": "2012-11-19T19:31:53.000Z", "title": "On the derivative of the α-Farey-Minkowski function", "authors": [ "Sara Munday" ], "categories": [ "math.DS" ], "abstract": "In this paper we study the family of $\\alpha$-Farey-Minkowski functions $\\theta_\\alpha$, for an arbitrary countable partition $\\alpha$ of the unit interval with atoms which accumulate only at the origin, which are the conjugating homeomorphisms between each of the $\\alpha$-Farey systems and the tent map. We first show that each function $\\theta_\\alpha$ is singular with respect to the Lebesgue measure and then demonstrate that the unit interval can be written as the disjoint union of the following three sets: $\\Theta_0:={x\\in\\U:\\theta_\\alpha'(x)=0}, \\Theta_\\infty:={x\\in\\U:\\theta_\\alpha'(x)=\\infty} and \\Theta_\\sim:=\\U\\setminus(\\Theta_0\\cup\\Theta_\\infty)$. The main result is that [\\dim_{\\mathrm{H}}(\\Theta_\\infty)=\\dim_{\\mathrm{H}}(\\Theta_\\sim)=\\sigma_\\alpha(\\log2)<\\dim_{\\mathrm{H}}(\\Theta_0)=1,] where $\\sigma_\\alpha(\\log2)$ is the Hausdorff dimension of the level set ${x\\in \\U:\\Lambda(F_\\alpha, x)=s}$, where $\\Lambda(F_\\alpha, x)$ is the Lyapunov exponent of the map $F_\\alpha$ at the point $x$. The proof of the theorem employs the multifractal formalism for $\\alpha$-Farey systems.", "revisions": [ { "version": "v1", "updated": "2012-11-19T19:31:53.000Z" } ], "analyses": { "keywords": [ "unit interval", "farey systems", "derivative", "arbitrary countable partition", "tent map" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1211.4541M" } } }