Events for 10/17/2017 from all calendars
Working Seminar in Orbit Equivalence and Measured Group Theory
Time: 10:00AM - 11:00AM
Location: BLOC 624
Speaker: Konrad Wrobel
Title: Stable Actions and Asymptotically Central Sequences I
Abstract: I'll be giving a characterization of stable actions in the sense of Jones-Schmidt using Kida's language of groupoids.
Nonlinear Partial Differential Equations
Time: 3:00PM - 4:00PM
Location: BLOC 628
Speaker: Xin Liu, Texas A&M University
Title: Nonlinear PDEs Seminar
Abstract:
Title: Some gas-vacuum interface problems of compressible Navier-Stokes equations in spherically symmetric motions
Abstract:
I will talk about the well-posedness of two problems concerning the evolution of a flow connected with vacuum. The flow, or gas, connects the vacuum area in a way that the sound speed across the gas-vacuum interface has only Holder continuity. A typical example is the Lane-Emden solution for gaseous stars, where the sound speed is only 1/2-Holder continuity on the gas-vacuum interface. As pointed out by T.P. Liu in 1996, the classical hyperbolic method fails due to such singularity. Only recently, Jang and Masmoudi, Coutand, Lindblad and Shkoller independently developed some weighted energy estimates to show the well-posedness of the inviscid isentropic flows. This work is to investigate how the viscosity will help resolve such singularity. In particular, the equilibrium and the well-posedness of a model based on the thermodynamic model listed in Chandrasekhar’s book (An introduction to the study of stellar structure) is studied. Also, we investigate the global well-posedness of the Navier-Stokes equations, which allows the density and velocity to be large, the gas to connect to vacuum in a general manner but the energy to be small. This is based on my Ph.D. thesis as a student of Prof. Zhouping Xin in the Chinese University of Hong Kong, Hong Kong. ===============
Analysis/PDE Reading Seminar
Time: 4:00PM - 5:00PM
Location: BLOC 624
Speaker: Robert Rahm, TAMU
Title: Asymptotic density of eigenvalues for 1 dimensional Schroedinger operators
Abstract: Consider the Schr\odinger Equation -y''(x) + q(x)y(x) = \lambda y(x) on $[0,\infty)$. We will initially assume only that q is non-negative and increasing and \lim_{x\to\infty}q(x) = \infty but will later put some restrictive assumptions on it. We will discuss the asymptotic density of eigenvalues of the equation. In particular, if N(T) is the number of eigenvalues less than T$ we will show: N(T) = \int_{0}^{q^{-1}(T)}\{T-q(x)\}^{1/2}dx + o(1).
Student/Postdoc Working Geometry Seminar
Time: 5:00PM - 6:00PM
Location: BLOC 628
Speaker: JM Landsberg, TAMU
Title: Geometry and Strassen's asymptotic sum conjecture
Sixth Annual Derivative Bee
Time: 7:00PM - 9:00PM
Location: BLOC 149