**Seminars and Colloquiums**

for the week of January 16, 2017

for the week of January 16, 2017

*SPEAKER:*

Dr. Yu-Ting Chen, UTK, Tuesday

Dr. Stefan Richter, UTK, Wednesday

Liem Nguyen, NCSU, Wednesday

Oliver Thistlewaite, UTK, Thursday

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

*Hosted by: Cara Sulyok*

**Tuesday, January 17th **

STOCHASTICS SEMINAR

TITLE: Organizational Meeting

SPEAKER: Dr. Yu-Ting Chen, UTK

TIME: 2:10pm - 3:25pm

ROOM: Ayres 113

All faculty and graduate students are welcome.

** Wednesday, January 18th **

ANALYSIS SEMINAR

TITLE: Interpolating sequences for multiplier algebras

SPEAKER: Dr. Stefan Richter, UTK

TIME: 2:30pm - 3:20pm

ROOM: Ayres G003

Interpolating sequences for the algebra of bounded analytic functions on the open unit disc were characterized by Carleson in 1958. Marshall/Sundberg and Bishop proved an analogous theorem for the multipliers of the Dirichlet space in 1994. By use of the recent solution to the Kadison-Singer problem by Marcus, Spielman, and Srivastava we show that the theorem holds for all spaces with complete Pick kernel.

JOINT DE/ CAM SEMINAR

TITLE: Global reconstruction methods for nonlinear inverse scattering problems

SPEAKER: Liem Nguyen, NCSU

TIME: 3:35pm – 4:25pm

ROOM: Ayres 113

This talk is about numerical methods for solving inverse problems arising from wave scattering. Potential applications of these problems include non-destructive testing, detection of explosives, medical imaging, geophysical prospection and radar. The major challenges in studying the numerical solution to these inverse problems are from the fact that the problems are highly nonlinear and ill-posed. The most developed approach in literature, which is nonlinear optimization schemes, typically requires good initial guesses for the solution since the objective functionals to minimize are in general not convex. However, these good initial guesses of the solution (or strong a-priori information of the solution) are not always available in many practical applications. The latter is the main reason for us to study global reconstruction methods, which do not rely on strong a-priori information of the solution, for solving nonlinear inverse problems. I will present in this talk two kinds of global methods as well as their numerical performance. This first one aims to solve a coefficient inverse problem with single measurement and the second is for a shape inverse problem for periodic structures.

**Thursday, January 19th **

JR. COLLOQUIUM

TITLE: Boolean Formulas, Hypergraphs, and Combinatorial Topology

SPEAKER: Oliver Thistlewaite, UTK

TIME: 3:40pm – 4:30pm

ROOM: Ayres 405

For this talk, our goal will be to study the shape of spaces of Boolean formulas. These formulas consist of variables which can be assigned TRUE or FALSE together with the logical operations AND, OR, and NOT. To do this, we will introduce a simplicial complex, called the theta complex, associated to any hypergraph. Simplicial complexes are a generalization of topological spaces one may obtain by gluing together line segments and solid triangles and a hypergraph is a generalization of a graph where an edge can connect any number of vertices.

*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:**