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Xueting Tian

Publications and source records attributed to Xueting Tian.

48 records · Page 3Linked to original sources

Diffeomorphisms with Liao-Pesin set

In this paper we mainly deal with an invariant (ergodic) hyperbolic measure $μ$ for a diffeomorphism $f,$ assuming that $f$ is just $C^1$ and for $μ$ a.e. $x$, the sum of Oseledec spaces corresponding to negative Lyapunov exponents (quasi-limit-)dominates the sum of Oseledec spaces corresponding to positive Lyapunov exponents at $x$. We generalize a certain of results of Pesin theory from $C^{1+α}$ to the $C^1$ system $ (f,μ)$, including a sufficient condition for existence of horseshoe, Livshitz theorem, exponential growth of periodic points, distribution of periodic points, periodic measures, horseshoes, nonuniform specification and lower semi-continuity of entropy function etc. In particular, they are applied for $C^1$ partially hyperbolic systems whose central bundle displays some non-uniform hyperbolicity, including some robust systems. Moreover, for some $C^1$ partially hyperbolic (not necessarily volume-preserving) systems, we get some information of Lebesgue measure on Average-nonuniform hyperbolicityand volume-non-expanding. A constructed machinery is developed for $C^1$ (not necessarily $C^{1+α}$) diffeomorphisms: new Pesin blocks is established topologically (independent on measures) such that every block has stable manifold theorem and simultaneously has exponential shadowing. The new construction, different with classical $C^{1+α}$ ones, is mainly inspired from Liao's quasi-hyperbolicity and so here we call new blocks by Liao-Pesin blocks and call the new established $C^1$ Pesin theory by $C^1$ Liao-Pesin Theory. Liao-Pesin set not only exists for invariant measures, but also exists for general probability measures, for example, Lebesgue measure (not assuming invariant) in some partially hyperbolic systems.

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Multifractal Analysis of The New Level Sets

By an appropriate definition, we divide the irregular set into level sets. Then we characterize the multifractal spectrum of these new pieces by calculating their entropies. We also compute the entropies of various intersections of the level sets of regular and irregular set which is rarely studied in the literature. Moreover, our conclusions also hold for the topological pressure. Finally, we consider the continuous case and use our results to give a description for the suspension flow.

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Dominated Splitting, Partial Hyperbolicity and Positive Entropy

Let $f:M\rightarrow M$ be a $C^1$ diffeomorphism with a dominated splitting on a compact Riemanian manifold $M$ without boundary. We state and prove several sufficient conditions for the topological entropy of $f$ to be positive. The conditions deal with the dynamical behaviour of the (non-necessarily invariant) Lebesgue measure. In particular, if the Lebesgue measure is $δ$-recurrent then the entropy of $f$ is positive. We give counterexamples showing that these sufficient conditions are not necessary. Finally, in the case of partially hyperbolic diffeomorphisms, we give a positive lower bound for the entropy relating it with the dimension of the unstable and stable sub-bundles.

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Nonexistence of Lyapunov Exponents for Matrix Cocycles

It follows from Oseledec Multiplicative Ergodic Theorem that the Lyapunov-irregular set of points for which the Oseledec averages of a given continuous cocycle diverge has zero measure with respect to any invariant probability measure. In strong contrast, for any dynamical system $f:X\rightarrow X$ with exponential specification property and a H$\ddot{\text{o}}$lder continuous matrix cocycle $A:X\rightarrow G (m,\mathbb{R})$, we show here that if there exist ergodic measures with different Lyapunov spectrum, then the Lyapunov-irregular set of $A$ is residual (i.e., containing a dense $G_δ$ set).

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Lyapunov `Non-typical' Points of Matrix Cocycles and Topological Entropy

It follows from Oseledec Multiplicative Ergodic Theorem (or Kingman's Sub-additional Ergodic Theorem) that the set of `non-typical' points for which the Oseledec averages of a given continuous cocycle diverge has zero measure with respect to any invariant probability measure. In strong contrast, for any H$\ddot{o}$der continuous cocycles over hyperbolic systems, in this article we show that either all ergodic measures have same Maximal Lyapunov exponents or the set of Lyapunov `non-typical' points have full topological entropy and packing topological entropy. Moreover, we give an estimate of Bowen Hausdorff entropy from below.

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Different Asymptotic Behavior versus Same Dynamical Complexity

For any dynamical system $T:X\rightarrow X$ of a compact metric space $X$ with $g-$almost product property and uniform separation property, under the assumptions that the periodic points are dense in $X$ and the periodic measures are dense in the space of invariant measures, we distinguish various periodic-like recurrences and find that they all carry full topological topological entropy and so do their gap-sets. In particular, this implies that any two kind of periodic-like recurrences are essentially different. Moreover, we coordinate periodic-like recurrences with (ir)regularity and obtain lots of generalized multi-fractal analysis for all continuous observable functions. These results are suitable for all $β-$shfits ($β>1$), topological mixing subshifts of finite type, topological mixing expanding maps or topological mixing hyperbolic diffeomorphisms, etc. Roughly speaking, we combine many different "eyes" (i.e., observable functions and periodic-like recurrences) to observe the dynamical complexity and obtain a {\it Refined Dynamical Structure} for Recurrence Theory and Multi-fractal Analysis.

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Non-uniform Hyperbolicity and Non-uniform Specification

In this paper we deal with an invariant ergodic hyperbolic measure $μ$ for a diffeomorphism $f,$ assuming that $f$ it is either $C^{1+α}$ or $f$ is $C^1$ 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, including \cite{STV,Y, PS, T,Var, Oli}. Our main results have several consequences: as corollaries, we are able to improve the results about quantitative Poincaré recurrence, removing the assumption of the non-uniform specification property in the main Theorem of \cite{STV} that establishes an inequality between Lyapunov exponents and local recurrence properties. Another consequence is the fact that any of such measure is the weak limit of averages of Dirac measures at periodic points, as in \cite{Sigmund}. Following \cite{Y} and \cite{PS}, one can show that the topological pressure can be calculated by considering the convenient weighted sums on periodic points, whenever the dynamics is positive expansive and every measure with pressure close to the topological pressure is hyperbolic.

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Diffeomorphisms with various $C^1$ stable properties

Let $M$ be a smooth compact manifold and $Λ$ be a compact invariant set. In this paper we prove that for every robustly transitive set $Λ$, $f|_Λ$ satisfies a $C^1-$generic-stable shadowable property (resp., $C^1-$generic-stable transitive specification property or $C^1-$generic-stable barycenter property) if and only if $Λ$ is a hyperbolic basic set. In particular, $f|_Λ$ satisfies a $C^1-$stable shadowable property (resp., $C^1-$stable transitive specification property or $C^1-$stable barycenter property) if and only if $Λ$ is a hyperbolic basic set. Similar results are valid for volume-preserving case.

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Ergodic Properties of Invariant Measures for C^{1+α} nonuniformly hyperbolic systems

For an ergodic hyperbolic measure $ω$ of a $C^{1+α}$ diffeomorphism, there is an $ω$ full-measured set $\tildeΛ$ such that every nonempty, compact and connected subset $V$ of $\mathbb{M}_{inv}(\tildeΛ)$ coincides with the accumulating set of time averages of Dirac measures supported at {\it one orbit}, where $\mathbb{M}_{inv}(\tildeΛ)$ denotes the space of invariant measures supported on $\tildeΛ$. Such state points corresponding to a fixed $V$ are dense in the support $supp(ω)$. Moreover, $\mathbb{M}_{inv}(\tildeΛ)$ can be accumulated by time averages of Dirac measures supported at {\it one orbit}, and such state points form a residual subset of $supp(ω)$. These extend results of Sigmund [9] from uniformly hyperbolic case to non-uniformly hyperbolic case. As a corollary, irregular points form a residual set of $supp(ω)$.

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Dominated Splitting and Pesin's Entropy Formula

Let $M$ be a compact manifold and $f:\,M\to M$ be a $C^1$ diffeomorphism on $M$. If $μ$ is an $f$-invariant probability measure which is absolutely continuous relative to Lebesgue measure and for $μ$ $a.\,\,e.\,\,x\in M,$ there is a dominated splitting $T_{orb(x)}M=E\oplus F$ on its orbit $orb(x)$, then we give an estimation through Lyapunov characteristic exponents from below in Pesin's entropy formula, i.e., the metric entropy $h_μ(f)$ satisfies $$h_μ(f)\geq\int χ(x)dμ,$$ where $χ(x)=\sum_{i=1}^{dim\,F(x)}λ_i(x)$ and $λ_1(x)\geqλ_2(x)\geq...\geqλ_{dim\,M}(x)$ are the Lyapunov exponents at $x$ with respect to $μ.$ Consequently, by using a dichotomy for generic volume-preserving diffeomorphism we show that Pesin's entropy formula holds for generic volume-preserving diffeomorphisms, which generalizes a result of Tahzibi in dimension 2.

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The Structure on Invariant Measures of $C^1$ generic diffeomorphisms

Let $Λ$ be an isolated non-trival transitive set of a $C^1$ generic diffeomorphism $f\in\Diff(M)$. We show that the space of invariant measures supported on $Λ$ coincides with the space of accumulation measures of time averages on one orbit. Moreover, the set of points having this property is residual in $Λ$ (which implies the set of irregular$^+$ points is also residual in $Λ$). As an application, we show that the non-uniform hyperbolicity of irregular$^+$ points in $Λ$ with totally 0 measure (resp., the non-uniform hyperbolicity of a generic subset in $Λ$) determines the uniform hyperbolicity of $Λ$.

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