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Marius Butzek

Publications and source records attributed to Marius Butzek.

3 recordsLinked to original sources

Non-uniform Berry--Esseen bounds for Gaussian, Poisson and Rademacher processes

In this paper we obtain non-uniform Berry-Esseen bounds for normal approximations by the Malliavin-Stein method. The techniques rely on a detailed analysis of the solutions of Stein's equations and will be applied to functionals of a Gaussian process like multiple Wiener-It\^o integrals, to Poisson functionals as well as to the Rademacher chaos expansion. Second-order Poincar\'e inequalities for normal approximation of these functionals are connected with non-uniform bounds as well. As applications, elements living inside a fixed Wiener chaos associated with an isonormal Gaussian process, like the discretized version of the quadratic variation of a fractional Brownian motion, are considered. Moreover we consider subgraph counts in random geometric graphs as an example of Poisson $U$-statistics, as well as subgraph counts in the Erd\H{o}s-R\'enyi random graph and infinite weighted 2-runs as examples of functionals of Rademacher variables.

math.PR

A surrogate by exchangeability approach to the Curie-Weiss model

We introduce a new general concept of surrogate random variable, the ``surrogate by exchangeability'' that allows to study the class of random variables that can be decomposed by means of an independent randomisation. As an example, we treat the case of the Curie-Weiss model using the explicit construction of its De Finetti measure of exchangeability. Writing the magnetisation as a sum of i.i.d.'s randomised by the underlying De Finetti random variable, the surrogate study shows that the appearance of a phase transition can be understood as a competition between these two sources of randomness, the Gaussian regime corresponding to a marginally relevant disordered system.

math.PR

Moderate Deviations for Functionals over infinitely many Rademacher random variables

In this paper, moderate deviations for normal approximation of functionals over infinitely many Rademacher random variables are derived. They are based on a bound for the Kolmogorov distance between a general Rademacher functional and a Gaussian random variable, continued by an intensive study of the behavior of operators from the Malliavin--Stein method along with the moment generating function of the mentioned functional. As applications, subgraph counting in the Erd\H{o}s--R\'enyi random graph and infinite weighted 2-runs are studied.

math.PR