We consider stationary stochastic processes arising from dynamical systems by evaluating a given observable along the orbits of the system. We focus on the extremal behaviour of the process, which is related to the entrance in certain regions of the phase space, which correspond to neighbourhoods of the maximal set M, i.e., the set of points where the observable is maximised. The main novelty here is the fact that we consider that the set M may have a countable number of points, which are associated by belonging to the orbit of a certain point, and may have accumulation points. In order to prove the existence of distributional limits and study the intensity of clustering, given by the Extremal Index, we generalise the conditions previously introduced in [FFT12, FFT15].
We consider stochastic processes arising from dynamical systems by evaluating
an observable function along the orbits of the system. The novelty is that we
will consider observables achieving a global maximum value (possible infinite)
at multiple points with special emphasis for the case where these maximal
points are correlated or bound by belonging to the same orbit of a certain
chosen point. These multiple correlated maxima can be seen as a new mechanism
creating clustering. We recall that clustering was intimately connected with
periodicity when the maximum was achieved at a single point. We will study this
mechanism for creating clustering and will address the existence of limiting
Extreme Value Laws, the repercussions on the value of the Extremal Index, the
impact on the limit of Rare Events Points Processes, the influence on
clustering patterns and the competition of domains of attraction. We also
consider briefly and for comparison purposes multiple uncorrelated maxima. The
systems considered include expanding maps of the interval such as Rychlik maps
but also maps with an indifferent fixed point such as Manneville-Pommeau maps
We consider diffeomorphisms of compact Riemmanian manifolds which have a Gibbs-Markov-Young structure, consisting of a reference set Λ with a hyperbolic product structure and a countable Markov partition. We assume polynomial contraction on stable leaves, polynomial backward contraction on unstable leaves, a bounded distortion property and a certain regularity of the stable foliation. We establish a control on the decay of correlations and large deviations of the SRB measure of the dynamical system, based on a polynomial control on the Lebesgue measure of the tail of return times. Finally, we present an example of a dynamical system defined on the torus and prove that it verifies the properties of the Gibbs-Markov-Young structure that we considered. 42
In this paper we prove a weak version of Lusin's theorem for the space of Sobolev-(1, p) volume preserving homeomorphisms on closed and connected n-dimensional manifolds, n ≥ 3, for p < n − 1. We also prove that if p > n this result is not true. More precisely, we obtain the density of Sobolev-(1, p) homeomorphisms in the space of volume preserving automorphisms, for the weak topology. Furthermore, the regularization of an automorphism in a uniform ball centered at the identity can be done in a Sobolev-(1, p) ball with the same radius centered at the identity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.