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José F. Alves

Publications and source records attributed to José F. Alves.

11 recordsLinked to original sources
arXiv2026

Decay of Correlations for Partially Hyperbolic Skew-Products

We develop a technique based on sectional transfer operators and the regularity of their fixed points to study rates of correlation decay for partially hyperbolic skew-products. To illustrate the range of applicability of this technique, we apply it to a family of Viana like maps with non-uniformly contracting fibres, a family of skew-product maps with non-uniformly expanding base dynamics and to a generalised family of heterochaos baker maps. The latter partially hyperbolic systems have recently been an active topic of research due to their connection with the Dyck shift.

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arXiv2026

Martingale Methods for Maximal Large Deviations and Young Towers

We develop a martingale approximation framework yielding quantitative maximal large deviations estimates for invertible dynamical systems. From suitable decay of correlations, we deduce these estimates and, as an application, we obtain Young structures with matching recurrence tails for partially hyperbolic diffeomorphisms with mostly expanding central direction. In a second application, we prove maximal large deviation estimates for systems modelled by Young towers with subexponential contraction and expansion. Many examples of slowly mixing billiards are covered by this result.

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arXiv2026

Linear response for skew-product maps with contracting fibres

We study linear response for families of skew-product dynamical systems with contracting fibres. Our approach is based on a sectional transfer operator acting on families of probability measures along the fibres. The operator allows to describe invariant measures of the skew-product in terms of sample measures over the base dynamics, regardless of invertibility or non-invertibility of the base map. Under general assumptions, we establish existence and uniqueness of invariant sample measures and prove their differentiability, with respect to system parameters, in suitable topologies. As an application we obtain linear response for Bernoulli convolutions, which are of prime importance in the study of number theoretic problems and fractals. Another application of our results yields linear response for physical measures of solenoidal attractors with intermittency, an example of a hyperbolic system which cannot be handled by traditional transfer operator techniques.

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arXiv2025

From decay of correlations to recurrence times in systems with contracting directions

Classic results by L.-S. Young show that the decay of correlations for systems that admit inducing schemes can be obtained through the recurrence rates of the inducing scheme. Reciprocal results were obtained for non-invertible systems (without contracting directions). Here, we obtain reciprocal results also for invertible systems (with contracting directions).

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arXiv2025

Young structures for partially hyperbolic systems with mostly contracting central direction

We establish the existence of Young structures for a broad class of partially hyperbolic diffeomorphisms with a splitting $TM = E^{cs} \oplus E^{uu}$, under exactly the same conditions that ensure the existence of SRB measures in a previous work by Bonatti and Viana. This extends the applicability of statistical techniques to systems where statistical properties remained largely unexplored. Our approach refines previous methods, introducing key adaptations to the partially hyperbolic setting. These results provide a foundation for obtaining decay of correlations, Central Limit Theorem, large deviations and a vector-valued almost sure invariance principle in this class of dynamical systems.

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arXiv2024

Impulsive Lorenz semiflows: Physical measures, statistical stability and entropy stability

We study semiflows generated via impulsive perturbations of Lorenz flows. We prove that such semiflows admit a finite number of physical measures. Moreover, if the impulsive perturbation is small enough, we show that the physical measures of the semiflows are close, in the weak* topology, to the unique physical measure of the Lorenz flow. A similar conclusion holds for the entropies associated with the physical measures.

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arXiv2023

Quenched decay of correlations for nonuniformly hyperbolic random maps with an ergodic driving system

In this article we study random tower maps driven by an ergodic automorphism. We prove quenched exponential correlations decay for tower maps admitting exponential tails. Our technique is based on constructing suitable cones of functions, defined on the random towers, which contract with respect to the Hilbert metric under the action of appropriate transfer operators. We apply our results to obtain quenched exponential correlations decay for several non-iid random dynamical systems including small random perturbations of Lorenz maps and Axiom A attractors.

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arXiv2013

Srb Measures For Almost Axiom A Diffeomorphisms

We consider a diffeomorphism f of a compact manifold M which is Almost Axiom A, i.e. f is hyperbolic in a neighborhood of some compact f-invariant set, except in some singular set of neutral points. We prove that if there exists some f-invariant set of hyperbolic points with positive unstable-Lebesgue measure such that for every point in this set the stable and unstable leaves are "long enough", then f admits a probability SRB measure.

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arXiv2010

From Rates of mixing to recurrence times via large deviations

A classic approach in dynamical systems is to use particular geometric structures to deduce statistical properties, for example the existence of invariant measures with stochastic-like behaviour such as large deviations or decay of correlations. Such geometric structures are generally highly non-trivial and thus a natural question is the extent to which this approach can be applied. In this paper we show that in many cases stochastic-like behaviour itself implies that the system has certain non-trivial geometric properties, which are therefore necessary as well as sufficient conditions for the occurrence of the statistical properties under consideration. As a by product of our techniques we also obtain some new results on large deviations for certain classes of systems which include Viana maps and multidimensional piecewise expanding maps.

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arXiv2005

On the nonexistence of fat partially hyperbolic horseshoes

We show that there are no partially hyperbolic horseshoes with positive Lebesgue measure for diffeomorphisms whose class of differentiability is higher than 1. This generalizes a classical result by Bowen for uniformly hyperbolic horseshoes.

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