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Triangle Topology Seminar: Nur Saglam, Georgia Tech , Fillability of Contact Structures on the 3-manifolds obtained by surgeries on the trefoil knot

SAS 4201

Let M be the 3-manifold obtained by r-surgery on the right handed trefoil knot. Classification of contact structures on such manifolds have been mostly understood for r\geq 1 and r=0. Etnyre-Min-Tosun has an upcoming work on the classification of the tight contact structures for all r. The fillability of contact structures on M is mostly understood if r is not…

Differential Equations and Nonlinear Analysis Seminar: Ayman Rimah Said, Duke University, Logarithmic spirals in 2d perfect fluids

SAS 4201

In this talk I will present recent results with In-Jeong from Seoul national university where we study logarithmic spiraling solutions to the 2d incompressible Euler equations which solve a nonlinear transport system on $\mathbb{S}$. We show that this system is locally well-posed in $L^p, p\geq 1$ as well as for atomic measures, that is logarithmic…

Pure Math Graduate Student Seminar: Alex Betz, NC State, Module Categories and Algebra Objects

SAS 2102

 When studying Tensor Categories we want to understand what algebra objects can be found in those categories. After finding such objects it's natural to consider their A -modules and more importantly the category of A (bi)-modules. This talk will attempt to explain this concept and enlighten listeners with motivating examples. Zoom Meeting link:  https://ncsu.zoom.us/j/92762214990?pwd=MnA1TnNVQUpzUlo3cTM5RmlNWVF4Zz09      Password:…

Numerical Analysis Seminar: Li Wang, University of Minnesota, Neural network based solvers for kinetic equations

SAS 4201

Deep learning method has emerged as a competitive mesh-free method for solving partial differential equations (PDEs). The idea is to represent solutions of PDEs by neural networks to take advantage of the rich expressiveness of neural networks representation. In this talk, we will explore the applicability of this powerful framework to the kinetic equation, which…

Biomathematics Seminar: Didong Li, UNC Chapel Hill, Inference for Gaussian processes on compact Riemannian manifolds

Cox 306

Gaussian processes (GPs) are widely employed as versatile modeling and predictive tools in spatial statistics, functional data analysis, computer modeling and diverse applications of machine learning. They have been widely studied over Euclidean spaces, where they are specified using covariance functions or covariograms for modelling complex dependencies. There is a growing literature on GPs over…

Graduate Training Seminar: Seyma Shabbir, NC State, Setting Up Your Webpage in WordPress

SAS 4201

Effective webpages are an increasingly important medium for disseminating information related to classes and research. For TAs, they provide a critical way to share material with your class whereas for those entering the job market, they are often checked by potential employers interested in obtaining more information about candidates. Hence it is important to construct…

Numerical Analysis Seminar: Pejman Sanaei, Georgia State University, On mathematical modeling and simulation of flight stability of objects, tissue engineering and droplets

SAS 4201

In this talk, I will present 3 problems on fluid structure interaction: 1) Flight stability of wedges: Recent experiments have shown that cones of intermediate apex angles display orientational stability with apex leading in flight. Here we show in experiments and simulations that analogous results hold in the two-dimensional context of solid wedges or triangular prisms in planar…

Geometry and Topology Seminar: Dilara Siraeva, Fulbright Scholar, NC State, Symmetry reduction of a gas dynamic system of PDEs with a special state function

SAS 4201

In this talk, I will present new results on the symmetry reduction of gas dynamic systems of PDEs following the general framework presented by  Lev Ovsyannikov in his article  "The “podmodeli” program. Gas dynamics" https://www.sciencedirect.com/science/article/pii/0021892894901376 The gas dynamics systems of equations, with an arbitrary state equation, has an 11-dimensional Lie algebra of symmetries which generates a group…

Algebra and Combinatorics Seminar: Andrew Harder, Lehigh University, The geometry of 2-loop Feynman integrals

SAS 2235

Speaker’s webpage: https://math.cas.lehigh.edu/andrew-harder In particle physics, many quantities of interest are expressed in terms of Feynman integrals. These integrals are attached to combinatorial objects called Feynman graphs, and can be expressed as integrals over (infinite) domains inside the real plane. In examples, one often finds that Feynman integrals are equal to special values of functions that…

Differential Equations and Nonlinear Analysis Seminar: Mihaela Ifrim, University of Wisconsin Madison, Global solutions for 1D cubic defocusing dispersive equations: Part I

SAS 4201

This article is devoted to a general class of one dimensional NLS problems with a cubic nonlinearity. The question of obtaining scattering, global in time solutions for such problems has attracted a lot of attention in recent years, and many global well-posedness results have been proved for a number of models under the assumption that…

Applied Math Graduate Student Seminar: Walker Powell, NC State, Model Reduction and Validation Tools for Large-Scale Models

SAS 1220

Of primary importance in computational science and applications is quantification and improvement of predictive capabilities of large-scale parameterized models, which often require the use of multi-query techniques that are intractable for computationally expensive models. This research focuses on three primary thrusts: sensitivity analysis, reduced-order modeling, and uncertainty quantification and algorithm and implementation choices that scale favorably…

Numerical Analysis Seminar: Koffi Enakoutsa and Xinghao Dong , UCLA, The Morrey Conjecture: Insights from Numerical Simulations on Quasi-Convexity and Rank-One Convexity.

Zoom

The Morrey Conjecture concerns quasi-convexity and rank-one convexity of functions. While the former implies the latter, it's unclear if the converse is true. Sverak proved the conjecture in 3D, but it remains unresolved in the planar case. Analyzing these properties analytically is difficult, especially for vector-valued functions, hence we perform numerical simulations using example functions…

Geometry Topology Seminar: Jacek Brodzki, University of Southampton, England, Topological Learning and disorder in structured nano materials

SAS 4201

Disorder is a fact of life, and controlling it on the nanoscale is complex, expensive, and of limited use. On the other hand, disordered materials do offer a range of possible applications if we know how to identify their useful features. To this end, we propose an approach through Topological Learning  to quantify disorder and…

Algebra and Combinatorics Seminar: Sean Sanford, The Ohio State University, Real Fusion Categories

SAS 2235

Fusion categories are algebraic gadgets that have seen many applications in topology and mathematical physics.  In particular, they can be used to encode topological quantum field theories in the sense of Atiyah.  Classical examples of fusion categories include C-Rep(G), the category of finite dimensional complex representations of a finite group G.  Because of their connections…

Differential Equations and Nonlinear Analysis Seminar: Mikhail Perepelitsa, University of Houston, Kinetic modeling of Myxobacteria motion with nematic alignment

SAS 4201

Motivated by motion of myxobacteria, we review several kinetic approaches for modeling motion of self-propelled, interacting rods. We will focus on collisional models of Boltzmann type and discuss the derivation of the governing equations, the range of their validity, and present some analytical and numerical results. We will show that collisional models have a natural…