**Seminars and Colloquiums**

for the week of October 10, 2016

for the week of October 10, 2016

*SPEAKER:*

Logan Higginbotham, UTK, Monday

Tricia Phillips, UTK, Monday

Jan Rosinski, UTK, Tuesday

Chase Worley, UTK, Wednesday

Prof. Zhu Wang, University of South Carolina, Wednesday

Tadele Mengesha, UTK, Thursday

Dr. Vitaly Ganusov, Math and Microbiology, UTK, Thursday

*TEA TIME -
3:00 pm – 3:30 pm
Monday, Tuesday, & Wednesday
Room: Ayres 401*

*Hosted by: Jesse Sautel & Jeahyun Park*

**Monday, October 10th **

TOPOLOGY/GEOMETRY SEMINAR

TITLE: Constructing a Groupoid over the Stone-Cech Compactification of a Discrete Space II

SPEAKER: Logan Higginbotham, UTK

TIME: 2:30pm – 3:20pm

ROOM: Ayres 114

Most of the talk is based off of chapter 10 of "Lectures on Coarse Geometry" by John Roe. We define a groupoid and show necessary and sufficient conditions of when $\beta X \times \beta X$ injects into $\beta (X \times X)$ for $X$ a discrete space. Using this and some consequences of partial bijections over a certain bounded geometric structure on $X$, we are able to then construct a groupoid over $\beta X$.

MATH BIOLOGY SEMINAR

TITLE: Long Distance Dispersal and Spread for Invasions

SPEAKER: Tricia Phillips, UTK

TIME: 2:30pm – 3:20pm

ROOM: Ayres G003

** Tuesday, October 11th **

STOCHASTICS SEMINAR

TITLE: Isomorphism identities for perturbed infinitely divisible processes, Part II

SPEAKER: Jan Rosinski, UTK

TIME: 2:10pm – 3:25pm

ROOM: Ayres 114

We consider infinitely divisible processes perturbed by an additive independent noise. We study admissible perturbations under which the perturbed process, which need not be infinitely divisible, is absolutely continuous with respect to the unperturbed process. The Dynkin's isomorphism theorem is an example of such phenomenon, where the local time of a Markov process is the perturbation.

** Wednesday, October 12th **

ANALYSIS SEMINAR

TITLE: Parametric Families of Commuting Squares, Part II

SPEAKER: Chase Worley, UTK

TIME: 2:30pm-3:20pm

ROOM: Ayres 003

We investigate analytic deformations of commuting squares arising from finite groups G. In the case G=Z_n, the associated commuting square corresponds to the Fourier matrix of size n, and its deformations correspond to n x n complex Hadamard matrices. This allows us to find deformations of the Fourier matrix in the manifold of complex Hadamard matrices, which is rare and usually hard to do.

Since we want to construct families of commuting squares, we will look at the direction in which they might converge. To do this, we will construct a basis of the tangent space of the commuting square. Then we will examine which directions in the tangent space yield analytic deformations. In doing so, we will be able to create multi-parametric families of commuting squares, and thus multi-parametric families of complex Hadamard matrices containing the Fourier matrix. Our work builds on the previous work of Nicoara and White.

COMPUTATIONAL AND APPLIED MATHEMATICS (CAM) SEMINAR

TITLE: Proper Orthogonal Decomposition Reduced-Order Modeling of Complex Fluid Flows

SPEAKER: Prof. Zhu Wang, University of South Carolina

TIME: 3:35pm – 4:35pm

ROOM: Ayres 113

In many scientific and engineering applications of complex fluid flows, computational efficiency is of paramount importance. However, because of the requisite of repeated numerical simulations in applications such as control, optimization, data assimilation, and uncertainty quantification, using the original system becomes prohibitive. Therefore, model reduction techniques have been frequently used by engineers and researchers. Among them, proper orthogonal decomposition is one of the most commonly used methods to generate reduced-order models for turbulent flows dominated by coherent structures. To achieve a balance between the low computational cost required by a reduced-order model and the complexity of the target turbulent flows, appropriate closure modeling strategies need to be employed. In this talk, we present reduced-order modeling strategies synthesizing ideas originating from proper orthogonal decomposition and large eddy simulation, develop rigorous error estimates and design efficient algorithms for the new reduced-order models.

**Thursday, October 13th **

DE SEMINAR

TITLE: A nonlocal Korn’s inequality

SPEAKER: Tadele Mengesha, UTK

TIME: 2:00 p.m.

ROOM: Ayres 112

I will discuss the classical Korn’s inequality and its application in existence of a solution to a linear system of PDEs. I will also discuss a possible formulation of a nonlocal Korn’s inequality, and prove this inequality for a particular class of functions.

JR. COLLOQUIUM

TITLE: Reproducibility in natural sciences: are all mathematical modeling-based studies fully reproducible?

SPEAKER: Dr. Vitaly Ganusov, Math and Microbiology

TIME: 3:40pm-4:30pm

ROOM: Ayres 405

In the past several years there have been many reports indicating inability of some authors to reproduce large percent of published studies, mainly in medicine and psychology. Some funding agencies such as the NIH have responded to such reports by changing guidelines for grant applications to include indications of reproducibility. Mathematical modeling is now becoming a commonly used tool to understand mechanisms of biological system. Yet, as far as I know there have been no studies investigating reproducibility of mathematical modeling studies. In my talk I will discuss the issue of reproducibility of scientific studies, how mathematical modeling may have contributed to this issue, and what steps we need to take to reduce the degree of unreproducibility in natural sciences including studies using mathematical modeling.

** Friday, October 14th **

NO COLLOQUIUM

*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:**