Non-uniform hyperbolicity and non-uniform specification

摘要

In this paper we deal with an invariant ergodic hyperbolic measure μ for a diffeomorphism f, assuming that f is either C~(1+α) or C~1 and the Oseledec splitting of μ is dominated. We show that this system (f,μ) satisfies a weaker and non-uniform version of specification, related with notions studied in several recent papers. Our main results have several consequences: as corollaries, we are able to improve the results about quantitative Poinca?e recurrence, removing the assumption of the non-uniform specification property in the main theorem of "Recurrence and Lyapunov exponents" by Saussol, Troubetzkoy and Vaienti that establishes an inequality between Lyapunov exponents and local recurrence properties. Another consequence is the fact that any such measure is the weak limit of averages of Dirac measures at periodic points, as in a paper by Sigmund. One can show that the topological pressure can be calculated by considering the convenient weighted sums on periodic points whenever the dynamic is positive expansive and every measure with pressure close to the topological pressure is hyperbolic.