Events for 10/10/2018 from all calendars

Noncommutative Geometry Seminar

Time: 2:00PM - 3:00PM

Location: BLOC 628

Speaker: Dean Baskin, Texas A&M University

Title: Diffraction for the Dirac equation with Coulomb-like potentials

Abstract: The Dirac equation describes the relativistic evolution of electrons and positrons. We consider the (time-dependent!) Dirac equation in three spatial dimensions coupled to a potential with Coulomb singularities. We show that singularities of the solutions are typically diffracted by the singularities of the potential and compute the symbol of the diffracted wave. In this talk I will 1) describe what I mean by diffraction in a simpler setting, 2) describe our results for the Dirac equation, and 3) ask the audience for help understanding these results in a more geometric way. This talk is based on joint work with Oran Gannot and Jared Wunsch.

Numerical Analysis Seminar

Time: 3:00PM - 4:00PM

Location: BLOC 628

Speaker: Ricardo Alonso

Title: Convergence and error estimates for a conservative spectral method for the homogeneous Boltzmann equation.

Abstract: Abstract: We develop error estimates for a semi-discrete conservative spectral method for the Boltzmann equation in L2 and Sobolev spaces. We prove that the conservation laws are, in some sense, more important than positivity of the solution in order to have accurate simulations for large times. Convergence of the numerical approximation to the Maxwellian equilibrium is also proved.

Groups and Dynamics Seminar

Time: 3:00PM - 4:00PM

Location: BLOC 220

Speaker: Slava Grigorchuk

Title: On the question: "Can one hear the shape of a group?" and Hulancki type theorem for graphs

Abstract: In my talk I will address the famous question of M.Kac (traced back to L.Bers and A.Weyl) "Can one hear the shape of a drum?" in the context of groups viewed as geometric objects. I will show that the answer in NO in a strong sense: there is a continuum family of 4-generated pairwise not quasi-isometric groups with the same spectrum of discrete Laplacian. Moreover each of these groups has uncountable family of amenable covering groups with the same spectrum. The arguments will be based on the construction by the speaker of groups of intermediate growth (between polynomial and exponential), and the results in the spectral theory of graphs which somehow is related to the famous Hulanicki criterion of amenability of groups in terms of weak containment of unitary representations. The talk is based on joint results with A.Dudko.

P&T Committee Meeting

Time: 4:00PM - 5:00PM

Location: BLOC 220

Description: All Full and Associate Professor's to discuss promotion candidates (continuation of first meeting).

AMUSE

Time: 6:00PM - 7:00PM

Location: BLOC 220

Speaker: Dr. Reza Langari, Department of Mechanical Engineering, Texas A&M University

Title: Computational Model of Human Driving for Autonomous Driving

Abstract: In this presentation, we consider how a combination of mathematical tools ranging from predictive modeling to game theory to Markov decision processes can be used to devise suitable models of human driving for automated vehicles. The intent is to show how human driving can be modeled in algorithmic form and used to design collision free path planning and control strategies for these vehicles. The use of mathematical tools is essential in this process as one must have efficient ways to represent human driving behavior. For instance, a multitude of rules of thumb will not be sufficient for the purpose at hand. These algorithms are matched against human driver behavior in driving simulator studies, thereby proving their effectiveness. We demonstrate the utility of the approach using high fidelity simulation models of multilane highway driving in mandatory and discretionary lane changing settings.