Skip to main content
College of Sciences
Department of Mathematics

Events

Events Search and Views Navigation

Event Views Navigation

Filters

Changing any of the form inputs will cause the list of events to refresh with the filtered results.

Today

Giulia Cavagnari, Politecnico di Milano, Italy, Evolution equations in Wasserstein spaces driven by dissipative probability vector fields: a variational approach

Zoom

In this talk we present well posedness of Measure Differential Equations, i.e. evolution equations in the Wasserstein space of probability measures driven by dissipative probability vector fields. We take inspiration from the theory of \emph{dissipative operators} in Hilbert spaces and of Wasserstein gradient flows of geodesically convex functionals. Our approach is based on a measure-theoretic…

Graduate Student Panel, What is a Prelim?

Zoom

Are you a graduate student that has to do a "Preliminary Oral Exam" at some point in the future?  Do you also have no idea what a "Preliminary Oral Exam" is?  This event is designed for you!  As part of the Graduate Training Modules series, MGSA is hosting a "What is a Prelim?" event consisting of…

Corey Jones, NC State, Fusion categories in mathematics and physics

SAS 4201

Fusion categories are algebraic structures that generalize the representation categories of finite groups. I will explain how fusion categories have become involved in diverse areas of mathematics and physics, from topologically ordered phases of matter in 2-dimensions to quantum symmetries of noncommutative spaces.   Jointly in person and virtually on Zoom. SAS 4201 for in-person…

Walker Powell, Convergence Acceleration for a 2-Level Iterative Neutronics Solution Scheme

Zoom

Accurate simulations of neutron transport within nuclear reactors are an important component in developing safe and efficient reactors and operation protocols. However, high-fidelity simulations of an entire core are often too costly for use in multi-query applications, such as multi-physics coupling, uncertainty quantification, or optimal experimental design. To facilitate efficient simulations, we utilize a simulation…

Qi Tang, Staff Scientist, Los Alamos National Laboratory, An adaptive, scalable fully implicit resistive MHD solver and its application in plasmoid instability

Zoom

The magnetohydrodynamics (MHD) equations are continuum models used in the study of a wide range of plasma physics systems. However, efficient numerical solution methods for MHD are extremely challenging due to disparate time and length scales, strong hyperbolic phenomena, and nonlinearity. Therefore the development of scalable, implicit MHD algorithms and high-resolution adaptive mesh refinement strategies…

Demetre Kazaras, Duke University, Calculating total mass with harmonic functions

SAS 4201

The ADM mass of an isolated gravitational system is a geometric invariant measuring the total mass due to matter and other fields. I'll describe how to compute this invariant (in 3 spatial dimensions) by studying harmonic functions as well as solutions to other elliptic equations. Recent results in this context will be presented, focusing on applications to…

Saverio Salzo, Istituto Italiano di Tecnologia, Italy, The iterative Bregman projection method and applications to Optimal Transport

Zoom

Iterative Bregman projections is a classical method to compute  Bregman projections onto an intersection of affine sets. In statistics it was applied to the adjustment of distributions to a priori known marginals, and is best known as the Iterative proportional fitting procedures. In this talk I will present novel results concerning such classical method as well…

Intermediate Latex Workshop

Zoom

Along with the following blurb: "Our AMS student chapter will be hosting an Intermediate Latex Workshop! The tutorial will be led by Jessica Stevens and Ashley Tharp, focusing on Beamer and Tikz. If you have any questions, don't hesitate to reach out to Jessica or Ashley." Zoom link: https://ncsu.zoom.us/j/92300217208

Andy Manion, NC State, Higher tensor products and Heegaard Floer homology

SAS 4201

I will discuss some algebraic aspects of recent work with Raphael Rouquier on a tensor product operation for categorified representations of U_q(gl(1|1)^+) and its connections to Heegaard Floer homology. Speaker’s webpage: https://sites.google.com/usc.edu/manion/home Jointly in person and virtually on Zoom. SAS 4201 for in-person participation. The Zoom link is sent out to the Algebra and Combinatorics…

John Darges, Extreme learning machines for variance-based global sensitivity analysis

Zoom

Variance-based global sensitivity analysis (GSA) provides useful measures, Sobol' indices, of how important individual input variables are to the output of a mathematical model. Traditional estimation of Sobol' indices by Monte Carlo methods can be unfeasible for models which are computationally expensive to evaluate. An appealing approach is to instead use a surrogate whose Sobol'…

Tim Reid, Examining Sensitivity Large Computational Problems on Early Termination of CG with Probabilistic Numerics

Zoom

Many large computational problems depend on solutions to systems of linear equations. One widely used method of solving systems of linear equations is the Conjugate Gradient method (CG). Terminating CG after only a few iterations can save computational resources but can also cause an error in the solution to the system of linear equations, and…

David Keyes, King Abdullah University of Science and Technology, Nonlinear Preconditioning for Implicit Solution of Discretized PDEs

Zoom

 Nonlinear preconditioning refers to transforming a nonlinear algebraic system to a form for which Newton-type algorithms have improved success through quicker advance to the domain of quadratic convergence. We place these methods, which go back at least as far as the Additive Schwarz Preconditioned Inexact Newton (ASPIN, 2002) in the context of a proliferation distinguished…

Larry Gu, University of Southern California, Decategorification of HFK_n(L)

Zoom

Using a definition of Euler characteristic for fractionally-graded complexes based on roots of unity, we show that the Euler characteristics of Dowlin’s “sl(n)-like” Heegaard Floer knot invariants HFK_n recover both Alexander polynomial evaluations and sl(n) polynomial evaluations at certain roots of unity for links in S^3. We show that the equality of these evaluations can…

Pierre Cardialaguet, Université Paris-Dauphine, France, Microscopic derivation of a traffic flow model with a bifurcation

Zoom

In this joint ongoing work with Nicolas Forcadel (INSA Rouen) we study traffic flows models with a bifurcation. The model consists in a single incoming road divided after a junction into several outgoing ones. There are basically two classes of models to describe this situation: microscopic models, which explain how each vehicle behaves  in function…

Kailash Misra, NC State, Affine Lie Algebras and Crystals

SAS 1102

Affine Lie algebras, also sometimes called current algebras, are infinite-dimensional analogs of finite-dimensional semisimple Lie algebras. The representation theory of affine Lie algebras has applications in many areas of mathematics (number theory, combinatorics, group theory, geometry, topology, etc.) and physics (conformal field theory, integrable systems, statistical mechanics, etc.). To study the combinatorial properties of affine Lie algebra…

Juan Villarreal Montoya, NC State, Logarithmic vertex algebras

Zoom

First, I will make a general introduction to vertex algebras. Then, I will mention some results of recent work with Bojko Bakalov on Logarithmic vertex algebras.   Jointly in person in SAS 4201 or virtually on Zoom. The Zoom link is sent out to the Algebra and Combinatorics mailing list, please contact Corey Jones at cmjones6@ncsu.edu to…

Ben Daniel, NC State, Analyzing a Randomized Algorithm for Rank-Revealing QR Factorizations

Zoom

A rank-revealing QR factorization (RRQR) of an mxn matrix A can be an efficient alternative to the singular value decomposition.  Given 1≤k<n,  the problem of computing an RRQR is selecting k linearly independent columns of A. In this talk, we discuss the RRQR and present an efficient two-staged randomized algorithm to compute one. We analyze…

Cashous Bortner, NC State, Identifiabiity of Linear Compartmental Tree Models

Zoom

A linear compartmental model is a linear ODE model which can be visualized by a directed graph.  Identifiability is the study of determining whether a model's parameter values can be inferred from the defining "input-output equation" under perfect conditions.  In this talk, I present a novel combinatorial formula for the computation of the coefficients of these…

Longfei Li, University of Louisiana at Lafayette, Numerical methods for fourth-order PDEs on overlapping grids with application to Kirchhoff-Love plates

Zoom

We propose novel numerical methods for solving a class of high-order hyperbolic PDEs on general geometries, which involve 2nd-order derivatives in time and up-to 4th-order derivatives in space. These PDEs are widely used in modeling thin-walled elastic structures such as beams, plates and shells, etc. High-order spatial derivatives together with general geometries bring a number…