**Seminars and Colloquiums**

for the week of October 2, 2017

for the week of October 2, 2017

*SPEAKERS*

Dr. Hector Santos-Villalobos, ORNL, Tuesday

Qun Liu, Jilin University, China, Tuesday

Vince Ervin, Clemson University, Wednesday **
**Thomas Weighill,UTK, Wednesday

*TEA TIME* - cancelled

*3:00 pm – 3:30 pm
Monday, Tuesday,
Wednesday
Ayres 401
Hosted By: *

**Tuesday, October 3rd **

**SACNAS STUDENT CHAPTER**

TITLE: SACNAS Student Organization

SPEAKER: Dr. Hector Santos-Villalobos, ORNL

TIME: 12:00p – 1:00p

ROOM: Min H. Kao Room 435

The Society for Advancement of Chicanos/Hispanics and Native Americans in Science invites you to a lecture on computational imaging and biometrics.

Dr. Santos-Villalobos is a computational scientist in the Imaging, Signals, and Machine Learning Group in the Electrical and Electronics Systems Research Division at Oak Ridge National Laboratory.

FREE PIZZA!!

**STOCHASTICS/PROBABILITY**

TITLE: Large deviations in generalized random graphs

SPEAKER: Qun Liu, Jilin Univ, China

TIME: 2:10p – 3:25p

ROOM: Ayres 113

Abstract: In this talk, I will briefly introduce some basic random graph theory and a novel model called generalized random graphs. Generalized random graphs are considered where the presence of absence of an edges depends on the weights of its nodes. Our main interest in this talk is to investigate large deviations for the number of edges per node in such a generalized random graph. When the node weights are chosen randomly, obstacles arise due to the fact that the independence between two edges no longer exists, our main tools are some results of large deviations for mixtures.

**Wednesday, October 4th **

**CAM SEMINAR**

TITLE: Regularity, and spectral type approximation, of the solution to the fractional order diffusion equation in 1-d.

SPEAKER: Vince Ervin, Clemson University

TIME: 3:35p – 4:35p

ROOM: Ayres 113

Abstract: Few results are known on the regularity of the solution to fractional order differential equations. In this presentation we will investigate the regularity of the solution to the fractional order diffusion equation in 1-d. The fractional order diffusion operator we investigate is motivated by considering the 1-d heat equation. For this operator we are able to give a precise characterization of the regularity of the solution. Next, for this fractional diffusion operator, we investigate generalized eigenfunctions and eigenvalues. Using these generalized eigenfunctions, a spectral type approximation scheme for the fractional order diffusion equation is proposed and analyzed. Numerical results are presented illustrating the regularity of the solution, and demonstrating the spectral type approximation method.

** TOPOLOGY/GEOMETRY**

TITLE: Group actions and the maximal Roe algebra III

SPEAKER: Thomas Weighill, UTK

TIME: 3:35p – 4:25p

ROOM: Ayres 404

Abstract:
The (maximal) Roe algebra is an important C*-algebra which appears in the index theory of non-compact complete Riemannian manifolds. It is also a coarse invariant, and so is naturally an object of study in coarse geometry. In a previous talk, we saw what it means for a group to act on a metric space by coarse equivalences and introduced a kind of "coarse quotient" which we call X_G. In this talk, we will begin to establish a relationship between the maximal Roe algebras of X and X_G for certain kinds of group action. This correspondence will involve the (full) crossed product of the Roe algebra with the group G. We will introduce all the necessary concepts from the theory of C* algebras, and recall the definition of the Roe algebra and its maximal version. This is joint work with Logan Higginbotham.

*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 *

**Past notices:**