Events
Tea and Cookies
SAS 4104Peter Markowich, University of Cambridge and University of Vienna, “A PDE system modeling biological network formation”
SAS 1102Transportation networks are ubiquitous as they are possibly the most important building blocks of nature. They cover microscopic and macroscopic length scales and evolve on fast to slow times scales. Examples are networks of blood vessels in mammals, genetic regulatory networks and signaling pathways in biological cells, neural networks in mammalian brains, venation networks in…
Wen-Shin Lee, University of Antwerp, “Sparse interpolation, Padé approximation, signal processing, and tensor decomposition”
SAS 4201A mathematical model is called sparse if it is a combination of only a few non-zero terms. The aim of sparse interpolation is to determine both the support of the sparse linear combination and the coefficients in the representation, from a small or minimal amount of data samples. This talk centers around multi-exponential models: A…
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!
Harbir Antil, George Mason University, “Fractional operators with inhomogeneous boundary conditions: analysis, control, and discretization”
SAS 4201In this talk we introduce new characterizations of spectral fractional Laplacian to incorporate nonhomogeneous Dirichlet and Neumann boundary conditions. The classical cases with homogeneous boundary conditions arise as a special case. We apply our definition to fractional elliptic equations of order s in (0,1) with nonzero Dirichlet and Neumann boundary conditions. Here the domain Omega…
Alejandro Adem, University of British Columbia, “Homotopy group actions and group cohomology”
SAS 4201Let G denote a finite group and X a CW-complex. A homotopy group action is defined as a homotopy class of maps BG -- BAut(X). In this talk we will analyze these actions using techniques from group cohomology. We will show how they relate to geometric actions and how they can be used to construct…
Deena Hannoun Giffen, “Simulating non-dilute transport in porous media using a TCAT-based model”
Advised by Ralph Smith.
Rainer Sinn, Georgia Tech, “Pythagoras numbers of real projective varieties”
The Pythagoras number of field F, studied in the theory of quadratic forms, is the smallest k such that every sum of squares in F is a sum of k squares. We will reinterpret this definition for coordinate rings of real projective varieties and discuss ways to give bounds on this invariant. A central concept…
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!
Michele Palladino, Penn State, “Growth model for tree stems and vines”
SAS 4201In this talk, we propose a model describing the growth of tree stems and vine, taking into account also the presence of external obstacles. The system evolution is described by an integral differential equation which becomes discontinuous when the stem hits the obstacle. The stem feels the obstacle reaction not just at the tip, but…
Dmitry Vagner, Duke University, “A smooth TQFT approach to sln homology”
SAS 4201Given a link diagram L, one can apply a Skein relation to each crossing to yield a cube of resolutions. These skein relations come from the braiding in the category of Uq(sln) representations. When n2, we have the Khovanov cube of resolutions with edge maps defined by (co)pants conordisms. We may then apply a smooth…
Mansoor Haider, NC State, “Exploiting analytical structure to develop accelerated numerical solutions in continuum modeling of materials”
SAS 2229In many modeling applications, the analytical structure of fundamental solutions to associated mathematical problems can be exploited to develop more efficient or robust numerical algorithms. I will present several examples of such approaches and techniques based on integral representations arising in the continuum modeling of materials. Some techniques to be discussed include asymptotic analysis, exploiting…
Tea and Cookies
SAS 4104Mark Giesbrecht, University of Waterloo, “Eigenvalues, invariant and random integer matrices”
SAS 1102Integer matrices are often characterized by the lattice of combinations of their rows or columns. This is captured nicely by the Smith canonical form, a diagonal matrix of invariant factors, to which any integer matrix can be transformed through left and right multiplication by unimodular matrices. Algorithms for computing Smith forms have seen dramatic improvements…
Elections and Ice Cream Social
SAS 3281Come relax with some free ice cream and AWM at our end of the year ice cream social! We will also be electing officers for next year at this event.
Mark Shimozono, Virginia Tech, “Quiver Hall-Littlewood symmetric functions and Kostka-Shoji polynomials”
SAS 1102We associate to any quiver a family of symmetric functions, defined by creation operators which are generalizations of Jing's creation operators. For the cyclic quiver the coefficient polynomials were studied by Finkelberg and Ionov. Shoji has recently shown that the single variable specialization of the Finkelberg-Ionov polynomials agree with polynomials he studied in relation to…
TAGMaC conference at Duke
Duke Physics Buiding Durham, NC, United StatesThis semester, the Duke University AMS and SIAM graduate student chapters will host the biannual Triangle Area Graduate Mathematics Conference (TAGMaC). The event will occur on Sunday April 23 in the Duke Physics Building. The plenary speaker will be new UNC Professor Dave Rose. The organizers are Hangjie Ji, Sarah Ritchey, Shan Shan, and Dmitry…