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Events

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 4104

Please 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 4201

In 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 4201

Given 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 2229

In 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…

Mark Giesbrecht, University of Waterloo, “Eigenvalues, invariant and random integer matrices”

SAS 1102

Integer 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 3281

Come 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 1102

We 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 States

This 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…

Nicholas Higham, University of Manchester, “Challenges in multivalued matrix functions”

SAS 1102

Multivalued matrix functions arise in solving various kinds of matrix equations. The matrix logarithm is the prototypical example. Another example is the Lambert W function of a matrix, which is much less well known but has been attracting recent interest. A theme of the talk is the importance of choosing appropriate principal values and making…

Weekly Brown Bag Lunch

SAS 4104

Please join us for our last weekly brown bag lunch of the year! 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!

Ephraim Bililign, Taylor Garnowski, William Reese and Brandon Summers, NC State Undergraduate Student Honors Presentations

1. Ephraim Bililign Title: Measuring the temperature of granular systems Abstract: Granular systems, or collections of athermal mesoscale particles, are immune to temperature in the conventional sense. Thus, to describe the behavior of an jammed assortment of grains, we turn to a modified thermodynamics built on forces and volumes. I will discuss the experimental measurements…