Events
Victor Magron, LAAS-CNRS, France, The quest of efficiency and certification in polynomial optimization
ZoomIn 2001, Lasserre introduced a nowadays famous hierarchy of relaxations, called the moment-sums of squares hierarchy, allowing one to obtain a converging sequence of lower bounds for the minimum of a polynomial over a compact semialgebraic set. Each lower bound is computed by solving a semidefinite program (SDP). There are two common drawbacks related to…
Samantha Kirk, NC State, How to Construct Representations of Twisted Toroidal Lie Algebras via Lattice Vertex Algebras
ZoomIf you take a simple finite-dimensional Lie algebra g and tensor it with the Laurent polynomials in one variable, then you will get an infinite-dimensional Lie algebra known as a loop algebra. Affine Lie algebras are the central extensions of such loop algebras and their representations have been of interest to several mathematicians. What happens if we tensor g with…
Mitchel Colebank, NC State, Computational modeling of patient specific pulmonary hemodynamics
ZoomChair: Mette Olufsen (msolufse@ncsu.edu, contact for Zoom access)
Carter Jameson, NC State, Data science and mathematical modeling approaches to studying collective motion
ZoomChair: Kevin Flores (kbflores@ncsu.edu, contact for Zoom access)
Lars Ruthotto, Emory University, Numerical Analysis Perspectives on Deep Neural Networks
ZoomThe resurging interest in deep learning is commonly attributed to advances in hardware and growing data sizes and less so to new algorithmic improvements. However, cutting-edge numerical methods are needed to tackle ever larger and more complex learning problems. In this talk, I will illustrate numerical analysis tools for improving the effectiveness of deep learning…
Roberto Cominetti, Universidad Adolfo Ibáñez, Chile, Convergence rates for Krasnoselskii-Mann fixed-point iterations
ZoomA popular method to approximate a fixed point of a non-expansive map is C is the Krasnoselskii-Mann iteration. This covers a wide range of iterative methods in convex minimization, equilibria, and beyond. In the Euclidean setting, a flexible method to obtain convergence rates for this iteration is the PEP methodology introduced by Drori and Teboulle…
Prerona Dutta, NC State, Metric entropy and nonlinear partial differential equations
ZoomChair: Tien Khai Nguyen, contact for Zoom access.
Vakhtang Putkaradze, Variational Methods for Active Porous Media
ZoomMany biological organisms are comprised of deformable porous media, with additional complexity of an embedded muscle. Using geometric variational methods, we derive the equations of motion for the dynamics of such active porous media. The use of variational methods allows to incorporate both the muscle action and incompressibility of the fluid and the elastic matrix…
Dylan Bates, NC State, Virtual reinforcement learning for balancing an inverted pendulum in real time
ZoomChair: Hien Tran (tran@ncsu.edu, contact for Zoom access)
Peter Pivovarov, University of Missouri, Stochastic functional inequalities and shadow systems
ZoomI will discuss stochastic geometry of random concave functions. In particular, I will explain how a "local" stochastic dominance underlies several functional inequalities. Emphasis will be on a notion of shadow systems for s-concave functions and their interplay with functional inequalities. Based on joint works with J. Rebollo Bueno.
Julia Plavnik, Indiana University, On odd-dimensional modular tensor categories
ZoomModular tensor categories arise naturally in many areas of mathematics, such as conformal field theory, quantum groups and Hopf algebras, low dimensional topology, representations of braid groups, and they have important applications in condensed matter physics, modeling topological phases of matter. In this talk, I will start by introducing the relevant concepts (modular, braided and…
Paul Cazeaux, The University of Kansas, Twisted, incommensurate layered materials: modeling, computations and topology
ZoomTwo-dimensional crystals have been intensely investigated both experimentally and theoretically since graphene was exfoliated from graphite. Physicists have recently developed the ability to stack one layer on another with a twist angle controlled to the scale of .1 degree with the goal of creating two dimensional materials with desired electronic, optical, and mechanical properties. Unusual…
Tyrus Berry, George Mason University, A Manifold Learning Approach to Boundary Value Problems
ZoomMesh-free methods for boundary value problems (BVPs) can be convenient on manifolds where generating a mesh may be difficult or when the manifold is not known explicitly but is determined by data. Moreover, BVPs are important in machine learning since they provide a rigorous method of regularization for many regression problems. In this talk we…
Woden Kusner, University of Georgia, Measuring chirality with the wind
ZoomThe question of measuring "handedness" is of some significance in both mathematics and in the real world. Propellors and screws, proteins and DNA, in fact *almost everything* is chiral. Can we quantify chirality? Or can we perhaps answer the question: "Are your shoes more left-or-right handed than a potato?" We can begin with the hydrodynamic…
Stanislaw Szarek, Case Western Reserve University/Sorbonne Université
ZoomZoom ID: 936 5420 1948 Password: the last four digits of the Zoom ID in reverse order
Hussam Al Daas, STFC, Rutherford Appleton Laboratory, Two-level Nyström—Schur preconditioner for symmetric positive definite matrices
ZoomRandomized methods are becoming increasingly popular in numerical linear algebra. However, few attempts have been made to use them in developing preconditioners. Our interest lies in solving large-scale sparse symmetric positive definite linear systems of equations where the system matrix is preordered to doubly bordered block diagonal form (for example, using a nested dissection ordering).…
Alessio Porretta, Università di Roma Tor Vergata, Long time behavior in mean field game systems
ZoomMean field game PDE systems were introduced by J-M. Lasry and P.-L. Lions to describe Nash equilibria in multi-agents dynamic optimization. In the simplest model, those are forward-backward systems coupling Hamilton-Jacobi with Fokker-Planck equations. In this talk I will discuss the long time behavior of second order systems in the periodic case under suitable stability…