Ergodic maximization problem for expanding maps with differentiable observables

Ergodicity for uniformly differentiable modulo $p$ functions on ${\mathbb Z}_p$

We provide an ergodicity criterion for uniformly differentiable modulo $p$ functions on ${\mathbb Z}_p$ in regard to the minimal level of the reduced functions by showing that ergodic conditions are explicitly found in terms of the coefficients of Mahler or van der Put for each prime $p.$ To this end, it is essential to give an alternative, natural proof of Memi$\acute{c}$'s result regarding Mahler's coefficients estimation for uniformly differentiable modulo $p$ functions on ${\mathbb Z}_p.$

$L^\infty$-estimation of generalized Thue-Morse trigonometric polynomials and ergodic maximization

Given an integer $q\ge 2$ and a real number $c\in [0,1)$, consider the generalized Thue-Morse sequence $(t_n^{(q;c)})_{n\ge 0}$ defined by $t_n^{(q;c)} = e^{2πi c S_q(n)}$, where $S_q(n)$ is the sum of digits of the $q$-expansion of $n$. We prove that the $L^\infty$-norm of the trigonometric polynomials $σ_{N}^{(q;c)} (x) := \sum_{n=0}^{N-1} t_n^{(q;c)} e^{2πi n x}$, behaves like $N^{γ(q;c)}$, where $γ(q;c)$ is equal to the dynamical maximal value of $\log_q \left|\frac{\sin qπ(x+c)}{\sin π(x+c)}\right|$ relative to the dynamics $x \mapsto qx \mod 1$ and that the maximum value is attained by a…

Teoría Ergódica de los Atractores Topológicos y Estadísticos (Ergodic Theory of Topological and Statistical Attractors) (Spanish)

This is a textbook, in Spanish, for an introductory short course that focusses on the ergodic properties of topological and statistical attractors. It is directed to graduate students in Mathematics and related Science, in particular to the students-participants of the XXVI Escuela Venezolana de Matemática. The first three chapters include a review of the basic concepts and properties of the ergodic theory and of the topological and differentiable dynamics of systems that evolve on discrete time. They do not require from the reader previous knowledge on Dynamical Systems. The latter three chap…

Ergodic theory of generic continuous maps

We study the ergodic properties of generic continuous dynamical systems on compact manifolds. As a main result we prove that generic homeomorphisms have convergent Birkhoff averages under continuous observables at Lebesgue almost every point. In spite of this, when the underlying manifold has dimension greater than one, generic homeomorphisms have no physical measure --- a somewhat strange result which stands in sharp contrast to current trends in generic differentiable dynamics. Similar results hold for generic continuous maps. To further explore the mysterious behaviour of $C^0$ generic dyna…

对称区间交换变换的无限扩张的遍历性质

Ergodic properties of infinite extension of symmetric interval exchange transformations

本文研究了对称区间交换变换的无限扩张的遍历性质，证明了特定余循环的斜积在遍历基下是遍历的，并在唯一遍历性假设下推广到更一般的函数，最后通过弱混合情形得到无限遍历指数。

A theorem of Besicovitch and a generalization of the Birkhoff Ergodic Theorem

A remarkable theorem of Besicovitch is that an integrable function $f$ on $\mathbb{R}^2$ is strongly differentiable if and only if its associated strong maximal function $M_S f$ is finite a.e. We provide an analogue of Besicovitch's result in the context of ergodic theory that provides a generalization of Birkhoff's Ergodic Theorem. In particular, we show that if $f$ is a measurable function on a standard probability space and $T$ is an invertible measure-preserving transformation on that space, then the ergodic averages of $f$ with respect to $T$ converge a.e. if and only if the associated er…