Events
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Junping Wang, NSF, “Primal-dual weak Galerkin finite element methods for PDEs”
SAS 4201This talk will introduce a primal-dual finite element method for variational problems where the trial and test spaces are different. The essential idea behind the primal-dual method is to formulate the original problem as a constrained minimization problem. The corresponding Euler-Lagrange formulation then involves the primal (original) equation and its dual with homogeneous data. The…
Weekly Brown Bag Lunch
SAS 4104Please join us for our weekly brown bag lunch! You bring your lunch, and we will bring a delicious treat. Everyone (not just women) is welcome to join or stop by for as long as they can!
McKay Sullivan, “Supersymmetric bilinear forms and oscillator algebras”
Many important Lie (super)algebras can be constructed using bosonic and fermionic oscillators. We introduce inhomogeneous supersymmetric bilinear forms on a complex superspace and show that they lead to oscillator-like superalgebras. We classify such forms for superspaces up to dimension 7 and mention a few examples of subalgebras obtained from the corresponding superalgebras. This talk is…
Hung Tran, University of Wisconsin Madison, “Some selection problems in the theory of viscosity solutions”
SAS 4201I will explain some interesting selection problems in nonlinear PDEs. The basic question is about how to select one good solution out of many reasonable ones. A question of this type led to the whole theory of viscosity solutions in 1980s. Then I will focus on the vanishing discount problem and describe the main results,…
Steve Campbell, NC State, “Who’s in control here?”
Control theory is an important topic in applied mathematics that is used in a number of disciplines. Its theoretical foundations involve several areas of mathematics. It is also a topic that is less well known at the undergraduate level. In this talk we will explain what control theory is and give several elementary examples of specific kinds of…
Emily Barnard, “Canonical join representation in algebraic combinatorics”
Advised by Nathan Reading.
Steven Desrochers, “Numerical study and feedback stabilization of a linear hydro-elasticity model”
Mann 301Advised by Lorena Bociu.
Bernd Sturmfels, University of California, Berkeley, “Gaussian mixtures and their tensors”
SAS 4201Mixtures of Gaussians are ubiquitous in data science. We give an introduction to the geometry of these statistical models, with focus on the tensors that represent their higher moments. The familiar theory of rank and borderrank for symmetric tensors is recovered when all covariance matrices are zero. Recent work with Carlos Amendola and Kristian Ranestad…
Weekly Brown Bag Lunch
SAS 4104Please join us for our weekly brown bag lunch! You bring your lunch, and we will bring a delicious treat. Everyone (not just women) is welcome to join or stop by for as long as they can!
Tea and Cookies
SAS 4104Wen Shen, Penn State, “Vanishing viscosity solutions for Riemann problems in polymer flooding”
SAS 4201We visit several models of polymer flooding in reservoir simulation. A special common feature shared by the models, i.e., the thermo-dynamics is decoupled from the hydro-dynamics, leads to a scalar conservation law with discontinuous flux. We discuss solution of Riemann problems as the vanishing viscosity limit. In particular, we show by counter examples that there exists…
Zach Hough, “Degree-optimal moving frames for rational curves”
I will present an algorithm that, for a given vector of n relatively prime polynomials in one variable over an arbitrary field, outputs an invertible matrix with polynomial entries such that it forms a degree-optimal moving frame for the rational curve defined by the input vector. From an algebraic point of view, the first column…
Dan Scofield, NC State
Solid, liquid, gas – we see these phases of matter all around us. But physicists have discovered exotic phases with strange properties, such as superfluids and superconductors. What kinds of phase transitions happen in an extremely cold, thin sheet of matter? What does this have to do with the field of math known as topology? In this talk we’ll…
Max Glick, University of Connecticut, “The Berenstein-Kirillov group and cactus groups”
Berenstein and Kirillov have studied the action of Bender-Knuth moves on semistandard tableaux. Losev has studied a cactus group action in Kazhdan-Lusztig theory; in type A this action can also be identified in the work of Henriques and Kamnitzer. We establish the relationship between the two actions. We show that the Berenstein-Kirillov group is a…