Metric attractors for smooth unimodal maps

Statistical properties of unimodal maps: physical measures, periodic orbits and pathological laminations

In this work, we relate the geometry of chaotic attractors of typical analytic unimodal maps to the behavior of the critical orbit. Our main result is an explicit formula relating the combinatorics of the critical orbit with the exponents of periodic orbits. This connection between topological and smooth invariants is obtained through an analysis of the physical measure. Since the exponents of periodic orbits form a complete set of smooth invariants in this setting, we have ``typical geometric rigidity'' of the dynamics of such chaotic attractors. This unexpected result implies that the lamina…

Topological properties of Lorenz maps derived from unimodal maps

A symmetric Lorenz map is obtain by ``flipping'' one of the two branches of a symmetric unimodal map. We use this to derive a Sharkovsky-like theorem for symmetric Lorenz maps, and also to find cases where the unimodal map restricted to the critical omega-limit set is conjugate to a Sturmian shift. This has connections with properties of unimodal inverse limit spaces embedded as attractors of some planar homeomorphisms.

Inverse limits as attractors in parameterized families

We show how a parameterized family of maps of the spine of a manifold can be used to construct a family of homeomorphisms of the ambient manifold which have the inverse limits of the spine maps as global attractors. We describe applications to unimodal families of interval maps, to rotation sets, and to the standard family of circle maps.

关于S-单峰映射的李雅普诺夫指数的存在性

Existence of the Lyapunov exponent for $S$-unimodal maps

研究S-单峰映射李雅普诺夫指数，证明非平坦临界点的该映射对几乎每个勒贝格点李雅普诺夫指数存在且为常数λ_T，给出其为0的充要条件，还得出相关特殊映射的结论。

Wild attractors and thermodynamic formalism

Fibonacci unimodal maps can have a wild Cantor attractor, and hence be Lebesgue dissipative, depending on the order of the critical point. We present a one-parameter family $f_λ$ of countably piecewise linear unimodal Fibonacci maps in order to study the thermodynamic formalism of dynamics where dissipativity of Lebesgue (and conformal) measure is responsible for phase transitions. We show that for the potential $ϕ_t = -t\log|f'_λ|$, there is a unique phase transition at some $t_1 \le 1$, and the pressure $P(ϕ_t)$ is analytic (with unique equilibrium state) elsewhere. The pressure is majorised…

Statistical properties of unimodal maps: smooth families with negative Schwarzian derivative

We prove that there is a residual set of families of smooth or analytic unimodal maps with quadratic critical point and negative Schwarzian derivative such that almost every non-regular parameter is Collet-Eckmann with subexponential recurrence of the critical orbit. Those conditions lead to a detailed and robust statistical description of the dynamics. This proves the Palis conjecture in this setting.

Robust Chaos and the Continuity of Attractors

As the parameters of a map are varied an attractor may vary continuously in the Hausdorff metric. The purpose of this paper is to explore the continuation of chaotic attractors. We argue that this is not a helpful concept for smooth unimodal maps for which periodic windows fill parameter space densely, but that for piecewise-smooth maps it provides a way to delineate structure within parameter regions of robust chaos and form a stronger notion of robustness. We obtain conditions for the continuity of an attractor and demonstrate the results with coupled skew tent maps, the Lozi map, and the bo…

Combinatorics, geometry and attractors of quasi-quadratic maps

The Milnor problem on one-dimensional attractors is solved for S-unimodal maps with a non-degenerate critical point c. It provides us with a complete understanding of the possible limit behavior for Lebesgue almost every point. This theorem follows from a geometric study of the critical set $ω(c)$ of a "non-renormalizable" map. It is proven that the scaling factors characterizing the geometry of this set go down to 0 at least exponentially. This resolves the problem of the non-linearity control in small scales. The proofs strongly involve ideas from renormalization theory and holomorphic dynam…

Smooth deformations of piecewise expanding unimodal maps

In the space of C^k piecewise expanding unimodal maps, k>=1, we characterize the C^1 smooth families of maps where the topological dynamics does not change (the "smooth deformations") as the families tangent to a continuous distribution of codimension-one subspaces (the "horizontal" directions) in that space. Furthermore such codimension-one subspaces are defined as the kernels of an explicit class of linear functionals. As a consequence we show the existence of C^{k-1+Lip} deformations tangent to every given C^k horizontal direction, for k>=2.

The multipliers of periodic points in one-dimensional dynamics

It will be shown that the smooth conjugacy class of an $S-$unimodal map which does not have a periodic attractor neither a Cantor attractor is determined by the multipliers of the periodic orbits. This generalizes a result by M.Shub and D.Sullivan for smooth expanding maps of the circle.

拓扑同步还是简单吸引子？

Topological synchronisation or a simple attractor?

本研究针对拓扑同步概念，以耦合两个logistic映射的斜积系统为例，证明其可解释为耦合强度增大时吸引子产生与边缘经验测度收敛，还发现对应吸引子的绝对连续物理测度在单峰映射下具多重分形结构。

Thick hyperbolic repelling invariant Cantor set and wild attractor

Let $D$ be the set of $β\in (1, 2]$ such that $f_β$ is a symmetric tent map with finite critical orbit. For $β\in D$, by operating Denjoy like surgery on $f_β$, we constructed a $C^1$ unimodal map $\tilde{g}_β$ admitting a thick hyperbolic repelling invariant Cantor set which contains a wild Cantor attractor. The smoothness of $\tilde{g}_β$ is ensured by the effective estimation of the preimages of the critical point as well as the prescribed lengths of the inserted intervals. Furthermore, $D$ is dense in $(1, 2]$, and $\tilde{g}_β$ can not be $C^{1+α}$ because the hyperbolic repelling invaria…

Non-smooth saddle-node bifurcations II: dimensions of strange attractors

We study the geometric and topological properties of strange non-chaotic attractors created in non-smooth saddle-node bifurcations of quasiperiodically forced interval maps. By interpreting the attractors as limit objects of the iterates of a continuous curve and controlling the geometry of the latter, we determine their Hausdorff and box-counting dimension and show that these take distinct values. Moreover, the same approach allows to describe the topological structure of the attractors and to prove their minimality.

具有一个拓扑吸引子的映射的 α-极限集与 Lyapunov 函数

α-limit sets and Lyapunov function for maps with one topological attractor

研究具有单一拓扑吸引子的连续映射，通过分层 $A$-$R$ 对分解刻画各点 α-极限集，并基于弱 Morse 分解构造有界 Lyapunov 函数以描述除贫集外的轨道行为。

The instantaneous local transition of a stable equilibrium to a chaotic attractor in piecewise-smooth systems of differential equations

An attractor of a piecewise-smooth continuous system of differential equations can bifurcate from a stable equilibrium to a more complicated invariant set when it collides with a switching manifold under parameter variation. Here numerical evidence is provided to show that this invariant set can be chaotic. The transition occurs locally (in a neighbourhood of a point) and instantaneously (for a single critical parameter value). This phenomenon is illustrated for the normal form of a boundary equilibrium bifurcation in three dimensions using parameter values adapted from of a piecewise-linear m…

Persistent massive attractors of smooth maps

For a smooth manifold of any dimension greater than one, we present an open set of smooth endomorphisms such that any of them has a transitive attractor with a non-empty interior. These maps are $m$-fold non-branched coverings, $m \ge 3$. The construction applies to any manifold of the form $S^1 \times M$, where $S^1$ is the standard circle and $M$ is an arbitrary manifold.

Physical Measures for Infinitely Renormalizable Lorenz Maps

A physical measure on the attractor of a system describes the statistical behavior of typical orbits. An example occurs in unimodal dynamics. Namely, all infinitely renormalizable unimodal maps have a physical measure. For Lorenz dynamics, even in the simple case of infinitely renormalizable systems, the existence of physical measures is more delicate. In this article we construct examples of infinitely renormalizable Lorenz maps which do not have a physical measure. A priori bounds on the geometry play a crucial role in (unimodal) dynamics. There are infinitely renormalizable Lorenz maps whic…

集值动力系统的吸引子光滑持续性：一种边界映射方法

Smooth Persistence of Attractors for Set-Valued Dynamical Systems: A Boundary Map Approach

针对随机、控制及不确定性传播建模场景下的集值动力系统，本文引入边界映射方法，借助切触几何与法向双曲条件证明了带光滑边界吸引子的扰动下光滑持续性。

Cherry flows with non trivial attractors

We provide an example of Cherry flow (i.e. smooth flow on the $2$-dimensional torus with a sink and a saddle) having quasi-minimal set which is an attractor. The first return map for such a flow, constructed also in the paper, is a smooth circle map having a flat interval and a non-trivial wandering interval.

Linear response formula for piecewise expanding unimodal maps

The average R(t) of a smooth function with respect to the SRB measure of a smooth one-parameter family f_t of piecewise expanding interval maps is not always Lipschitz. We prove that if f_t is tangent to the topological class of f_0, then R(t) is differentiable at zero, and the derivative coincides with the resummation previously proposed by the first named author of the (a priori divergent) series given by Ruelle's conjecture.

Nonhyperbolicity of invariant measures on maximal attractor

The article states that for every compact manifold M of dimension 4 or higher there is an area U in a set of smooth diffeomorphisms over M such that every map f from U has local maximal partially hyperbolic attractor and nonatomic ergodic invariant measure on it where one of Lyapunov exponents vanish. The result is first proved for skew products over horseshoe and then transferred onto smooth diffeomorphisms.

The creation of strange non-chaotic attractors in non-smooth saddle-node bifurcations

We propose a general mechanism by which strange non-chaotic attractors (SNA) are created during the collision of invariant curves in quasiperiodically forced systems. This mechanism is first discussed on an heuristic level and by means of simulations. In the considered examples, a stable and an unstable invariant circle undergo a saddle-node bifurcation, but instead of a neutral invariant curve there exists a strange non-chaotic attractor-repeller pair at the bifurcation point. This process is accompanied by a very characteristic behaviour of the invariant curves prior to their collision, whic…

A test for a conjecture on the nature of attractors for smooth dynamical systems

Dynamics arising persistently in smooth dynamical systems ranges from regular dynamics (periodic, quasiperiodic) to strongly chaotic dynamics (Anosov, uniformly hyperbolic, nonuniformly hyperbolic modelled by Young towers). The latter include many classical examples such as Lorenz and Hénon-like attractors and enjoy strong statistical properties. It is natural to conjecture (or at least hope) that most dynamical systems fall into these two extreme situations. We describe a numerical test for such a conjecture/hope and apply this to the logistic map where the conjecture holds by a theorem of Ly…

Piecewise smooth one dimensional maps with nowhere vanishing derivative

We consider the dynamics of `nonlinear tent maps': piecewise smooth unimodal maps with nowhere vanishing derivative. We show that if a nonlinear tent map $f$ is not infinitely renormalizable, then all its periodic orbits of sufficiently high period are hyperbolic repelling. If additionally all periodic orbits of $f$ are hyperbolic, then $f$ has at most finitely many periodic attractors and there is a hyperbolic expansion outside the basins of these periodic attractors. In particular, if a nonlinear tent map $f$ is not infinitely renormalizable and all its periodic orbits are hyperbolic repelli…

关于单峰映射拓扑同步的一个注记

A note on the topological synchronisation of unimodal maps

本文解答了文献[CGSV]中主从配置单峰映射拓扑同步的问题，计算了耦合强度趋近0和1时不变测度的弱极限，证明了随机动力系统不变测度唯一性及马尔可夫链几何收敛性。

Alternative proofs of linear response for piecewise expanding unimodal maps

We give two new proofs that the SRB measure of a C^2 path f_t of unimodal piecewise expanding C^3 maps is differentiable at 0 if f_t is tangent to the topological class of f_0. The arguments are more conceptual than the one in our previous paper, but require proving Holder continuity of the infinitesimal conjugacy (a new result, of independent interest) and using spaces of bounded p-variation. The first new proof gives differentiability of higher order if f_t is smooth enough and stays in the topological class of f_0 and if the observable smooth enough (a new result). In addition, this proof d…

Generalized Attracting Horseshoes and Chaotic Strange Attractors

A generalized attracting horseshoe is introduced as a new paradigm for describing chaotic strange attractors (of arbitrary finite rank) for smooth and piecewise smooth maps f from Q to Q, where Q is a homeomorph of the unit interval in real m-space for any integer m > 1. The main theorems for generalized attracting horseshoes are shown to apply to Henon and Lozi maps, thereby leading to rather simple new chaotic strange attractor existence proofs that apply to a range of parameter values that includes those of earlier proofs.

Continuity of attractors for $\mathcal{C}^1$ perturbations of a smooth domain

We consider a family of semilinear parabolic problems with nonlinear boundary conditions \[ \left\{ \begin{aligned} u_t(x,t) &=Δu(x,t) -au(x,t) + f(u(x,t)),\ x \in Ω_ε\mbox{ and } t>0\,,\\ \displaystyle\frac{\partial u}{\partial N}(x,t) &=g(u(x,t)),\ x \in \partialΩ_ε\mbox{ and } t>0\,, \end{aligned} \right. \] where $Ω_0 \subset \mathbb{R}^n$ is a smooth (at least $\mathcal{C}^2$) domain , $Ω_ε = h_ε(Ω_0)$ and $h_ε$ is a family of diffeomorphisms converging to the identity in the $\mathcal{C}^1$-norm. Assuming suitable regularity and dissipative conditions for the nonlinearites, we show that …

对称Fibonacci双峰映射存在野生吸引子

Wild attractor exists for symmetric Fibonacci bimodal map

本文证明对称Fibonacci双峰映射在临界阶足够大时，其临界点的公共ω-极限集为野生Cantor吸引子，并通过半共轭将问题简化为Fibonacci盒映射。

Smooth Morse-Lyapunov Functions and Morse Theory of Strong Attractors for Nonsmooth Dynamical Systems

In this paper we first construct smooth Morse-Lyapunov functions of attractors for nonsmooth dynamical systems. Then we prove that all open attractor neighborhoods of an attractor have the same homotopy type. Based on this basic fact we finally introduce the concept of critical group for Morse sets of an attractor and establish Morse inequalities and equations.

Power law asymptotics in the creation of strange attractors in the quasi-periodically forced quadratic family

Let $Φ$ be a quasi-periodically forced quadratic map, where the rotation constant $ω$ is a Diophantine irrational. A strange non-chaotic attractor (SNA) is an invariant (under $Φ$) attracting graph of a nowhere continuous measurable function $ψ$ from the circle $\mathbb{T}$ to $[0,1]$. This paper investigates how a smooth attractor degenerates into a strange one, as a parameter $β$ approaches a critical value $β_0$, and the asymptotics behind the bifurcation of the attractor from smooth to strange. In our model, the cause of the strange attractor is a so-called torus collision, whereby an attr…

Structure and regularity of the global attractor of a reaction-di§usion equation with non-smooth nonlinear term

In this paper we study the structure of the global attractor for a reaction- di§usion equation in which uniqueness of the Cauchy problem is not guarantied. We prove that the global attractor can be characterized using either the unstable manifold of the set of stationary points or the stable one but considering in this last case only solutions in the set of bounded complete trajectories.

Pathwise solutions and attractors for retarded SPDEs with time smooth diffusion coefficients

In this paper we study the longtime dynamics of mild solutions to retarded stochastic evolution systems driven by a Hilbert-valued Brownian motion. As a preparation for this purpose we have to show the existence and uniqueness of a cocycle solution of such an equation. We do not assume that the noise is given in additive form or that it is a very simple multiplicative noise. However, we need some smoothing property for the coefficient in front of the noise. The main idea of this paper consists of expressing the stochastic integral in terms of non-stochastic integrals and the noisy path by usin…

Absorbing Cantor sets in dynamical systems: Fibonacci maps

In this paper we shall show that there exists a polynomial unimodal map f: [0,1] -> [0,1] which is 1) non-renormalizable(therefore for each x from a residual set, $ω(x)$ is equal to an interval), 2) for which $ω(c)$ is a Cantor set, and 3) for which $ω(x)=ω(c)$ for Lebesgue almost all x. So the topological and the metric attractor of such a map do not coincide. This gives the answer to a question posed by Milnor.

一般非均匀双曲单峰映射光滑形变的线性响应

Linear response for smooth deformations of generic nonuniformly hyperbolic unimodal maps

本文证明缓慢回归的C^4单峰映射族中，绝对连续不变测度对参数可微依赖，并给出Benedicks-Carleson映射不变测度的新表示及扭曲上同调方程的可解性。

Whitney-Holder continuity of the SRB measure for transversal families of smooth unimodal maps

We consider C^2 families t->f_t of C^4 nondegenerate unimodal maps. We study the absolutely continuous invariant probability (SRB) measure m_t of f_t, as a function of t on the set of Collet-Eckmann (CE) parameters: Upper bounds: Assuming existence of a transversal CE parameter, we find a positive measure set D of CE parameters, and, for each s in D, a subset D0 of D of polynomially recurrent parameters containing s as a Lebesgue density point, and constants C>1, G >4, so that, for every 1/2-Holder function A (of 1/2-Holder norm |A|) and all t in D0, |\int A dm_t -\int A dm_s| < C |A| |t-s|^{1…

Non-smooth saddle-node bifurcations III: strange attractors in continuous time

Non-smooth saddle-node bifurcations give rise to minimal sets of interesting geometry built of so-called strange non-chaotic attractors. We show that certain families of quasiperiodically driven logistic differential equations undergo a non-smooth bifurcation. By a previous result on the occurrence of non-smooth bifurcations in forced discrete time dynamical systems, this yields that within the class of families of quasiperiodically driven differential equations, non-smooth saddle-node bifurcations occur in a set with non-empty C2-interior.

Explosion of smoothness for conjugacies between multimodal maps

Let $f$ and $g$ be smooth multimodal maps with no periodic attractors and no neutral points. If a topological conjugacy $h$ between $f$ and $g$ is $C^{1}$ at a point in the nearby expanding set of $f$, then $h$ is a smooth diffeomorphism in the basin of attraction of a renormalization interval of $f$. In particular, if $f:I \to I$ and $g:J \to J$ are $C^r$ unimodal maps and $h$ is $C^{1}$ at a boundary of $I$ then $h$ is $C^r$ in $I$.

一类非一致双曲吸引子的关联衰减

Decay of Correlations for some Non-Uniformly Hyperbolic Attractors

针对光滑实现问题，研究非一致双曲吸引子动力系统的关联衰减，通过对一致双曲微分同胚施加减速程序构造系统，证明其关联存在多项式上下界，结果适用于Smale-Williams螺线及其小扰动。

Asymmetric unimodal maps with non-universal period-doubling scaling laws

We consider a family of strongly-asymmetric unimodal maps $\{f_t\}_{t\in [0,1]}$ of the form $f_t=t\cdot f$ where $f\colon [0,1]\to [0,1]$ is unimodal, $f(0)=f(1)=0$, $f(c)=1$ is of the form and $$f(x)=\left\{ \begin{array}{ll} 1-K_-|x-c|+o(|x-c|)& \mbox{ for }x<c, \\ 1-K_+|x-c|^β+ o(|x-c|^β) &\mbox{ for }x>c, \end{array}\right. $$ where we assume that $β>1$. We show that such a family contains a Feigenbaum-Coullet-Tresser $2^\infty$ map, and develop a renormalization theory for these maps. The scalings of the renormalization intervals of the $2^\infty$ map turn out to be super-exponential and…

Trajectory and smooth attractors for Cahn-Hilliard equations with inertial term

The paper is devoted to a modification of the classical Cahn-Hilliard equation proposed by some physicists. This modification is obtained by adding the second time derivative of the order parameter multiplied by an inertial coefficient which is usually small in comparison to the other physical constants. The main feature of this equation is the fact that even a globally bounded nonlinearity is "supercritical" in the case of two and three space dimensions. Thus the standard methods used for studying semilinear hyperbolic equations are not very effective in the present case. Nevertheless, we hav…

Universality but no rigidity for two-dimensional perturbations of almost commuting pairs

In this paper we consider two-dimensional dissipative maps of the annulus which are small perturbations of one-dimensional critical circle maps. It has been shown earlier that such perturbations admit an attractor which is a non-smooth topolgical circle - a "critical" circle. We study conjugacies of the maps that admit such attractors and show that although the maps exhibit universality - they approach a certain normal form when looked at small scales - two maps in general can not be smoothly comjugate on their critical attractors. This result extends the paradigm of "universality but no rigid…

Non-Smooth Saddle-Node Bifurcations of Forced Monotone Interval Maps I: Existence of an SNA

We study one-parameter families of quasi-periodically forced monotone interval maps and provide sufficient conditions for the existence of a parameter at which the respective system possesses a non-uniformly hyperbolic attractor. This is equivalent to the existence of a sink-source orbit, that is, an orbit with positive Lyapunov exponent both forwards and backwards in time. The attractor itself is a non-continuous invariant graph with negative Lyapunov exponent, often referred to as "SNA". In contrast to former results in this direction, our conditions are C^2-open in the fibre maps. By applyi…

高效计算随机动力系统平稳测度及李雅普诺夫景观

Efficient computation of stationary measures and the Lyapunov Landscape for families random dynamical systems with smooth additive noise

本文提出一种高效方法，用于计算具有光滑加性噪声的随机动力系统的平稳测度及李雅普诺夫景观，研究噪声诱导秩序的转变现象。

The periodic points of renormalization

It will be shown that the renormalization operator, acting on the space of smooth unimodal maps with critical exponent greater than 1, has periodic points of any combinatorial type.

微分正性特征化一维通常超曲吸引子

Differential positivity characterizes one-dimensional normally hyperbolic attractors

本文研究了一维光滑动力系统中通常超曲吸引子的微分正性特征，揭示其与光滑锥场的点wise微小收缩关系，类比零维超曲吸引子的微分稳定性特征。

Unfolding chaotic quadratic maps --- parameter dependence of natural measures

We consider perturbations of quadratic maps $f_a$ admitting an absolutely continuous invariant probability measure, where $a$ is in a certain positive measure set $\mathcal{A}$ of parameters, and show that in any neighborhood of any such an $f_a$, we find a rich fauna of dynamics. There are maps with periodic attractors as well as non-periodic maps whose critical orbit is absorbed by the continuation of any prescribed hyperbolic repeller of $f_a$. In particular, Misiurewicz maps are dense in $\mathcal{A}$. Almost all maps $f_a$ in the quadratic family is known to possess a unique natural measu…

Ergodic theory for smooth one-dimensional dynamical systems

In this paper we study measurable dynamics for the widest reasonable class of smooth one dimensional maps. Three principle decompositions are described in this class : decomposition of the global measure-theoretical attractor into primitive ones, ergodic decomposition and Hopf decomposition. For maps with negative Schwarzian derivative this was done in the series of papers [BL1-BL5], but the approach to the general smooth case must be different.

Elements of contemporary mathematical theory of dynamical chaos. Part 1. Pseudohyperbolic attractors

The paper deals with topical issues of modern mathematical theory of dynamical chaos and its applications. At present, it is customary to assume that dynamical chaos in finitedimensional smooth systems can exist in three different forms. This is dissipative chaos, the mathematical image of which is a strange attractor; conservative chaos, for which the entire phase space is a large "chaotic sea" with randomly spaced elliptical islands inside it; and mixed dynamics, characterized by the principal inseparability in the phase space of attractors, repellers and conservative elements of dynamics. I…

通过非线性阻尼将能量临界波动方程稳定至有限维吸引子

Stabilizing Energy-Critical Wave Equation to a Finite Dimensional Attractor via Nonlinear Damping

该研究针对三维有界区域上带能量临界源和非线性阻尼的波动方程，利用增强耗散等方法，证明其存在全局吸引子，在原点阻尼强单调假设下可稳定至有限维光滑集合，还建立了指数吸引子存在性。

Quasisymmetric robustness of the Collet-Eckmann condition in the quadratic family

We consider quasisymmetric reparametrizations of the parameter space of the quadratic family. We prove that the set of quadratic maps which are either regular or Collet-Eckmann with polynomial recurrence of the critical orbit has full Lebesgue measure. (The intent of this work is just to be a rigorous reference for the companion preprint Statistical properties of unimodal maps: smooth families with negative Schwarzian derivative. It is based on the LaTeX file of the paper Statistical properties of unimodal maps: the quadratic family. The proofs are very similar and in many places differ just b…

环面吸引子熵的普适下界

Universal bounds on the entropy of toroidal attractors

本文研究环面吸引子的拓扑熵，依据纯拓扑性质给出下界，证明其光滑吸引动力学要么熵至少为 $\log 2$，要么存在平稳动力学使熵为零。

混沌吸引子中的本质动力学

Essential dynamics in chaotic attractors

本文证明生成充分复杂异宿结的 $S^3$ 光滑向量场必然产生无穷多在光滑扰动下持续存在的周期轨道，并据此关联 Template 且基于 Thurston-Nielsen 分类定理得出三维流存在混沌动力学的拓扑判据，成功应用于研究 Rössler 和 Lorenz 吸引子。

Teichmüller space of Fibonacci maps

According to Sullivan, a space ${\cal E}$ of unimodal maps with the same combinatorics (modulo smooth conjugacy) should be treated as an infinitely-dimensional Teichmüller space. This is a basic idea in Sullivan's approach to the Renormalization Conjecture. One of its principle ingredients is to supply ${\cal E}$ with the Teichmüller metric. To have such a metric one has to know, first of all, that all maps of ${\cal E}$ are quasi-symmetrically conjugate. This was proved [Ji] and [JS] for some classes of non-renormalizable maps (when the critical point is not too recurrent). Here we consider a…