MenuEvents for 11/16/2018 from all calendars
Probability Seminar
Time: 10:00AM - 11:00AM
Location: BLOC 220
Speaker: Eviatar B. Procaccia, TAMU
Title: Stationary harmonic measure and DLA on the upper half plane
Abstract: In this talk we define a version of the harmonic measure which is stationary with respect to left-right translation of the upper planar lattice. We show that this infinite stationary harmonic measure is a proper scaling limit of the classical harmonic measure. It remains open to prove that one can use the stationary harmonic measure to construct a stationary - ergodic version of diffusion limited aggregation.
Probability Seminar
Time: 11:30AM - 12:30PM
Location: BLOC 220
Speaker: Gordan Zitkovic, UT Austin
Title: On a class of globally solvable quadratic systems of backward stochastic differential equations and applications
Abstract: Backward stochastic differential equations (BSDE) emerged as a unifying language of many seemingly separate applications of stochastic analysis. While the scalar case has been well understood for almost two decades, systems are still far out of reach, even though their applications are by no means in short supply. After a short introduction to BSDEs aimed at a generic probabilist and a survey of classical results, some recent progress on fully coupled systems with quadratic nonlinearities will be described. Several applications, including stochastic equilibria in incomplete financial markets, stochastic differential games, and martingales on Riemannian manifolds will also be discussed. Joint work with Hao Xing.
Probability Seminar
Time: 1:30PM - 2:30PM
Location: BLOC 220
Speaker: Eliza O'Reilly, UT Austin
Title: Couplings of determinantal point processes and their reduced Palm distributions and quantifying repulsiveness
Abstract: Determinantal point processes (DPPs) are a useful class of random point configurations exhibiting repulsion between points. We will describe their appealing properties and discuss a recent result on obtaining the reduced Palm distribution of a DPP by removing at most one point from the DPP. This result will be used to discuss the nature of repulsiveness of DPPs in terms of this removed point, and specific parametric models for DPPs will be compared. Additionally, we will discuss repulsion of DPPs in high dimensions and an application to high dimensional determinantal Boolean models. This talk is based on joint works with Jesper Møller and François Baccelli.
Mathematical Physics and Harmonic Analysis Seminar
Time: 1:50PM - 2:50PM
Location: BLOC 628
Speaker: Jari Taskinen, University of Helsinki
Title: Structure and existence of gaps of essential spectra of elliptic boundary problems in periodic waveguides
Abstract: We review some recent joint works with Sergei Nazarov and others concerning spectral elliptic boundary value problems in periodic waveguides. We consider the structure of the essential spectrum e.g. for the Neumann Laplacian in the case of a doubly periodic perforated plane subject to periodic or non-periodic, non-compact perturbations. We also deal with the existence, number and position of spectral gaps in the case of the elasticity and piezoelectricity systems in waveguides with thin structures.
Working Seminar in Groups, Dynamics, and Operator Algebras
Time: 2:00PM - 2:50PM
Location: BLOC 506A
Speaker: Jintao Deng, Texas A&M University
Title: Topological full groups of one-sided shifts of finite type VI
Colloquium - Jingwei Hu
Time: 3:00PM - 4:00PM
Location: BLOC 117
Speaker: Jingwei Hu, Purdue University
Description: Title: Asymptotic-preserving and positivity-preserving numerical methods for a class of stiff kinetic equations
Abstract:
Kinetic equations play an important role in multiscale modeling hierarchy. It serves as a basic building block that connects the microscopic particle models and macroscopic fluid models. Numerically approximating kinetic equations presents several difficulties: 1) high-dimensionality (the equation is in phase space); 2) nonlinearity and stiffness of the collision/interaction terms; 3) positivity of the solution (the unknown is a probability density function); 4) consistency to the limiting fluid models; etc. I will start with a brief overview of the kinetic equations including the Boltzmann equation and the Fokker-Planck equation, and then discuss in particular our recent effort of constructing efficient and robust numerical methods for these equations, overcoming some of the aforementioned difficulties.
Probability Seminar
Time: 3:00PM - 4:00PM
Location: BLOC 220
Speaker: Luiz Renato Fontes, University of Sao Paulo and NYU Shanghai
Title: Contact processes with general inter-recovery times
Abstract: We study the contact process in d dimensions with the usual exponential infection times, of rate lambda, but with general recovery times, rather than just the usual exponential recovery times. We seek conditions on the common distribution F of the recovery times in order to have survival (of the infection, with positive probability) for either 1) all λ>0; or 2) only for λ large enough. Regarding 1), such a condition is that F satisfies some regularity conditions evocative of, but going considerably beyond, inclusion in the basin of attraction of a stable law with index less than 1. And 2) holds if a) F has two moments (by a standard, simple argument); or (more involvedly) if b) F has a greater than 1 moment and (for technical reasons) d = 1, and also F has a decreasing hazard rate. We will introduce the model and results in detail, and explain the main ideas and steps in our proofs. Joint work with Domingos Marchetti, Tom Mountford and Maria Eulália Vares.
Geometry Seminar
Time: 4:00PM - 5:00PM
Location: BLOC 628
Speaker: Giulio Belletti, Scuola Normale Superiore, Pisa
Title: Asymptotics of Turaev-Viro invariants and volume
Abstract: The basic building block of many quantum invariants of 3-manifolds and links is the quantum 6j-symbol. In this talk, I will introduce this object and show how it can produce the Turaev-Viro invariants of 3-manifolds. Furthermore, I will talk about a recent joint work with Detcherry, Kalfagianni and Yang giving an asymptotically sharp upper bound on the 6j-symbol, implying the Turaev-Viro volume conjecture for an interesting infinite family of hyperbolic 3-manifolds. If time permits, I will also briefly discuss some applications of these results to the study of quantum invariants.
Linear Analysis Seminar
Time: 4:00PM - 5:00PM
Location: BLOC 624
Speaker: Matthew Fleeman, Baylor University
Title: Hyponormal Toeplitz Operators Acting on the Bergman Space
URL: Event link
