# Events for March 26, 2018 from General and Seminar calendars

## Linear Analysis Seminar

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 628

**Speaker:** Pierre Tarrago, CIMAT

**Title:** *Subordination methods for free deconvolution*

**Abstract:**The classical deconvolution of measures is an important problem which consists in recovering the distribution of a random variable from the knowledge of the random variable modified by an independent noise with known distribution. In this talk, I will discuss the free version of this problem: how can we recover the distribution of a non-commutative random variable from the knowledge of the distribution of the random variable modified by the addition (or multiplication) of a free independent noise ? Since large independent random matrices in general positions are approximately free, an answer to the former question is a first step in the extraction of the spectral distribution of a large matrix from the knowledge of the matrix with an additive or multiplicative noise. Contrary to the classical case, the free convolution is not described by an integral kernel like the Fourier transform. This problem has been circumvented by Biane, Voiculescu, Belinschi and Bercovici which developed a fixed point method called subordination. I will explain how this method can be used to reduce the free deconvolution problem to a classical one. This is a joint work with Octavio Arizmendi (CIMAT) and Carlos Vargas (CIMAT).

## Probability Seminar

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 220

**Speaker:** Pierre Tarrago, CIMAT

**Title:** *Subordination methods for free deconvolution*

**Abstract:**The classical deconvolution of measures is an important problem which consists in recovering the distribution of a random variable from the knowledge of the random variable modified by an independent noise with known distribution. In this talk, I will discuss the free version of this problem: how can we recover the distribution of a non-commutative random variable from the knowledge of the distribution of the random variable modified by the addition (or multiplication) of a free independent noise? Since large independent random matrices in general positions are approximately free, an answer to the former question is a first step in the extraction of the spectral distribution of a large matrix from the knowledge of the matrix with an additive or multiplicative noise. Contrary to the classical case, the free convolution is not described by an integral kernel like the Fourier transform. This problem has been circumvented by Biane, Voiculescu, Belinschi and Bercovici which developed a fixed point method called subordination. I will explain how this method can be used to reduce the free deconvolution problem to a classical one. This is a joint work with Octavio Arizmendi (CIMAT) and Carlos Vargas (CIMAT).

## Geometry Seminar

**Time:** 3:00PM - 4:00PM

**Location:** BLOC 628

**Speaker:** Cris Negron, MIT

**Title:** *Cohomology for Drinfeld doubles of finite group scheme*

**Abstract:**In the mid 2000’s Etingof and Ostrik conjectured that the cohomology H*(A,F) of any finite dimensional Hopf algebra A over an arbitrary field F is itself a finitely generated algebra, under the standard (Yoneda) product. This conjecture was motivated, in part, by fantastic work of Friedlander and Suslin from the 90’s, in which they showed that any finite group scheme in characteristic p has finitely generated cohomology. I will discuss joint work with E. Friedlander, where we return to the finite characteristic setting to provide a strong analysis of cohomology for so-called Drinfeld doubles of finite group schemes. I will discuss the central role such doubles play in the more general theory of finite tensor categories, and explain how the cohomology of such doubles can be understood via “classical” data.

## Working Seminar in Groups, Dynamics, and Operator Algebras

**Time:** 3:00PM - 3:50PM

**Location:** BLOC 506A

**Speaker:** Xin Ma, Texas A&M University

**Title:** *Groups acting on trees*

## Industrial and Applied Math

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 220

**Speaker:** Peter Kuchment

**Title:** *Mesmerizing Mathematics of Imaging*

## Student/Postdoc Working Geometry Seminar

**Time:** 5:00PM - 6:00PM

**Location:** BLOC 628

**Speaker:** P. Sarin, TAMU

**Title:** *Tensor networks*