{ "id": "0811.1809", "version": "v7", "published": "2008-11-12T03:06:25.000Z", "updated": "2011-02-15T10:06:57.000Z", "title": "Measures and dimensions of Julia sets of semi-hyperbolic rational semigroups", "authors": [ "Hiroki Sumi", "Mariusz Urbanski" ], "comment": "Published in Discrete and Continuous Dynamical Systems Ser. A., Vol 30, No. 1, 2011, 313--363. 50 pages, 2 figures", "journal": "Discrete and Continuous Dynamical Systems Ser. A., Vol 30, No. 1, 2011, 313--363", "categories": [ "math.DS", "math.CV", "math.PR" ], "abstract": "We consider the dynamics of semi-hyperbolic semigroups generated by finitely many rational maps on the Riemann sphere. Assuming that the nice open set condition holds it is proved that there exists a geometric measure on the Julia set with exponent $h$ equal to the Hausdorff dimension of the Julia set. Both $h$-dimensional Hausdorff and packing measures are finite and positive on the Julia set and are mutually equivalent with Radon-Nikodym derivatives uniformly separated from zero and infinity. All three fractal dimensions, Hausdorff, packing and box counting are equal. It is also proved that for the canonically associated skew-product map there exists a unique $h$-conformal measure. Furthermore, it is shown that this conformal measure admits a unique Borel probability absolutely continuous invariant (under the skew-product map) measure. In fact these two measures are equivalent, and the invariant measure is metrically exact, hence ergodic.", "revisions": [ { "version": "v7", "updated": "2011-02-15T10:06:57.000Z" } ], "analyses": { "subjects": [ "37F35", "37F15" ], "keywords": [ "julia set", "semi-hyperbolic rational semigroups", "probability absolutely continuous invariant", "nice open set condition holds", "borel probability absolutely continuous" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 50, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0811.1809S" } } }