{ "id": "1602.07809", "version": "v1", "published": "2016-02-25T05:58:52.000Z", "updated": "2016-02-25T05:58:52.000Z", "title": "Entropy of Isometries Semi-groups of Hyperbolic space", "authors": [ "Paul Mercat" ], "comment": "in French", "categories": [ "math.MG", "math.DS", "math.GR", "math.NT" ], "abstract": "We give a generalization to convex co-compact semigroups of a beautiful theorem of Patterson-Sullivan, telling that the critical exponent (that is the exponential growth rate) equals the Hausdorff dimension of the limit set (that is the smallest closed non-empty invariant subset), for a isometries discrete group of a proper hyperbolic space with compact boundary. To do that, we introduce a notion of entropy, which generalize the notion of critical exponent of discrete groups, and we show that it is equal to the upper bound of critical exponents of Schottky sub-semigroups (which are semigroups having the simplest dynamic). We obtains several others corollaries, such that the lower semi-continuity of the entropy, the fact that the critical exponent of a separate semigroup, that is defined as an upper limit, is in fact a true limit, and we obtain the existence of \"big\" Schottky sub-semigroups in discrete groups of isometries.", "revisions": [ { "version": "v1", "updated": "2016-02-25T05:58:52.000Z" } ], "analyses": { "keywords": [ "hyperbolic space", "isometries semi-groups", "critical exponent", "schottky sub-semigroups", "smallest closed non-empty invariant subset" ], "note": { "typesetting": "TeX", "pages": 0, "language": "fr", "license": "arXiv", "status": "editable" } } }