## Seminars and Colloquiums for the week of September 21, 2015

SPEAKER:

Ryan Jensen, UTK, Monday
Bo Gao, UTK, Tuesday
John Cummings Nick Dexter, Peter Jantsch, Nathan Pollesch, UTK, Wednesday
Tom Lewis, UNC-Greensboro, Wednesday
Buddi Pantha, UTK, Friday
David Horton, UTK, Friday
Zahra Sinaei, Northwestern University, Friday
Zahra Sinaei, Northwestern University, Friday

Tea Time, Monday & Tuesday, Hosted by Nate Pollesch

Monday September 21

ALGEBRA SEMINAR
TITLE: Unimodular rows and Hermite rings 1
TIME: 3:35 – 4:25pm
ROOM: Ayres 114
SPEAKER: Ryan Jensen, UTK
ABSTRACT: This is the first series of four talks whose aim is to present a proof (from a book by T.Y. Lam) of the fact that polynomial ring in n-variables over a field is a Hermite ring.

Tuesday September 22

STOCHASTICHS SEMINAR
TITLE:  Asymptotics for Brownian motion in Poissonian potential with Riesz kernel
TIME: 2:10 pm -3:25
ROOM: Ayres 114
SPEAKER: Bo Gao, UTK
ABSTRACT: In this talk, we will investigate the quenched long term asymptotics for the Brownian motion in a Poissinian potential with Riesz shape functions.

Wednesday September 23

TIME: 10:00 – 11:00pm
ROOM: Ayres 405
SPEAKER: John Cummings Nick Dexter, Peter Jantsch, Nathan Pollesch, UTK
ABSTRACT: For this week's GSS, we'll have an opportunity to hear from some of our fellow graduate students who are working out at Oak Ridge.  They'll discuss their research, mentors, which programs they're affiliated with, and any opportunities for graduate students who may also be interested in working at ORNL.  This will be followed by and Q&A session.

COMPUTATIONAL & APPLIED MATHEMATICS (CAM) SEMINAR
TITLE: Distributional Derivatives and the Stability of DG Methods
TIME: 3:35 -4:35pm
ROOM: Ayres 112
SPEAKER: Tom Lewis, UNC- Greensboro
ABSTRACT: The goal of the talk is to explore and motivate stabilization requirements for various types of discontinuous Galerkin (DG) methods. A new approach for the understanding of DG approximation methods for second order elliptic partial differential equations will be introduced. The main idea is to relate the underlying DG gradient approximation to distributional derivatives instead of the traditional piecewise gradient operator associated with broken Sobolev spaces. The approach naturally explains the weaker stability requirements for local discontinuous Galerkin (LDG) methods when compared to interior-penalty discontinuous Galerkin methods while also motivating the existence of methods such as the minimal dissipation LDG method that are stable without the addition of interior penalization terms.

Friday September 25

MATH BIOLOGY SEMINAR
TITLE: Invasion by Stratified Diffusion
TIME: 10:10 -11:00am
ROOM: Ayres 405
SPEAKER: Buddhi Pantha, UTK

GEOMETRY/TOPOLOGY
TITLE: Convergence of Harmonic Maps
TIME: 2:00 - 2:50
ROOM: Ayres 405
SPEAKER: Zahra Sinaei , Northwestern University
ABSTRACT: In this talk I will present a compactness theorem for a sequence of harmonic maps which are defined on a converging sequence of Riemannian manifolds. The sequence of manifolds will be considered in the space of compact n-dimensional Riemannian manifolds with bounded sectional curvature and bounded diameter, equipped with measured Gromov-Hausdorff topology.

ANALYSIS SEMINAR
TITLE: The Loewner equation driven by the Weierstrass function
TIME: 2:30 - 3:20
ROOM: BU 476
SPEAKER: David Horton
ABSTRACT: We'll finish what was started last week and see a technique for identifying phase changes for families of deformations driven by "difficult" functions. In particular, we'll prove a phase change for the Weierstrass function.

MATH COLLOQUIUM
TITLE: Intrinsic Flat Convergence of Covering Spaces
TIME: 3:30 - 4:30pm
ROOM: Ayres 405
SPEAKER: Zahra Sinaei, Northwestern University
ABSTRACT: Abstract: In this talk, we discuss the limits of covering spaces and the covering spectra of oriented Riemannian manifolds, $M_j$, which converge to a nonzero integral current space, $M_\infty$, in the intrinsic flat sense. We provide examples demonstrating that the covering spaces and covering spectra need not converge in this setting. Nevertheless, we show that if the $\delta$- covers, $\tilde{M}_j^\delta$, have finite order, then a subsequence of the $\tilde{M}_j^\delta$converge in the intrinsic flat sense to a metric space, $M^\delta_\infty$, which is the disjoint union of covering spaces of $M_\infty$. This is joint work with Christina Sormani.

### If you are interested in giving or arranging a talk for one of our seminars or colloquiums, please review our calendar.

If you have questions, or a date you would like to confirm, please contact colloquium AT math DOT utk DOT edu

###### last updated: May 2018

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College of Arts & Sciences

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