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Events

Algebra and Combinatorics Seminar: Nicholas Russoniello, Willam & Mary,

SAS 2225

Jointly in person and virtually on Zoom. SAS 2225 for in-person participation. The Zoom link is sent out to the Algebra and Combinatorics mailing list, please contact Corey Jones at cmjones6@ncsu.edu to be added.   Speaker’s webpage: https://www.wm.edu/as/mathematics/faculty-directory/russoniello_n.php

Pure Math Graduate Student Seminar: Ashley Tharp, NC State, Arcs and shards

SAS 2235

The group of permutations is the canonical example of a finite Coxeter group, and each permutation can be represented visually by a noncrossing arc diagram. Each diagram encodes the canonical join representation of its permutation, and diagrams can be used to understand lattice congruences on the weak order of type A, equivalence relations that respect the…

Applied Math Graduate Student Seminar: Alexander Mendez, NC State, Extreme Events in Natural Phenomena

SAS 4201

Extreme events are events that have an extremely low probability of occurring, but often have immense consequences. For this presentation, we focus on extreme events in climate change and wildfires. In the context of climate change, we examine the avoidance of so-called climate tipping points, which are climate regimes where small changes significantly alter the…

Numerical Analysis: Malik Hassanaly, National Renewable Energy Laboratory (NREL), Generative models and scientific sampling

Zoom

Realistic image generation has benefited from recent groundbreaking advances in the ML community. At the core of generative models lies the capability to sample high-dimensional distributions with relatively small support and a priori unknown shape. In many scientific applications, this capability is a limiting factor that has led to modeling choices that circumvent the sampling…

Geometry and Topology Seminar: Joey Zou, Northwestern, Microlocal Methods for The Elastic Travel Time Tomography Problem for Transversely Isotropic Media

Zoom

I will discuss the travel time tomography problem for elastic media in the transversely isotropic setting. The mathematical study of this problem relates to X-ray tomography and boundary rigidity problems studied by de Hoop, Stefanov, Uhlmann, Vasy, et al., which reduce the inverse problems to the microlocal analysis of certain operators obtained from a pseudolinearization…

Algebra and Combinatorics Seminar: Seth Sullivant, NC State, Maximum Agreement Subtrees

SAS 2225

BSTRctProbability distributions on the set of trees are fundamental in evolutionary biology, as models for speciation processes. These probability models for random trees have interesting mathematical features and lead to difficult questions at the boundary of combinatorics and probability. This talk will be concerned with the question of how much two random trees have in…

Differential Equations and Nonlinear Analysis Seminar: Alexei Novikov, PSU, USA, Long-time behavior of a randomly perturbed oscillator

Zoom

We consider a long-time behavior of a stochastically forced nonlinear oscillator. In a long-time limit the force converges to fractional Brownian motion, a process that has memory. In contrast, we show that the  limit of the nonlinear oscillator driven by this force converges to diffusion driven by standard (not fractional) Brownian motion, and thus retains…

Teaching and Learning Seminar: Bevin Maultsby, NC State, MATLAB Grader Workshop

SAS 4201

We will look at the brand new MATLAB Grader functionality in Moodle, featuring examples, tips and tricks, and a few drawbacks. Participants are encouraged to activate their MathWorks account first (https://www.mathworks.com/, use your Unity credentials) and bring a laptop to experiment with. If you would like to be a student in a Moodle Project space…

Colloquium: Thomas J.R. Hughes, University of Texas at Austin, The Finite Element Method and Computational Mechanics: Past, Present, and a Vision of the Future

Zoom

I will begin by probing into the past to discover the origins of the Finite Element Method (FEM), and then trace the evolution of those early developments to the present day in which the FEM is ubiquitous in science, engineering, mathematics, and medicine, and the most important discretization technology in Computational Mechanics. However, despite its…

Differential Equations and Nonlinear Analysis Seminar: Theodore D. Drivas, Stony Brook University, Remarks on the long-time dynamics of 2D Euler

Zoom

We will discuss some old and new results concerning the long-time behavior of solutions to the two-dimensional incompressible Euler equations. Specifically, we discuss whether steady states can be isolated, wandering for solutions starting nearby certain steady states, singularity formation at infinite time, and finally some results/conjectures on the infinite-time limit near and far from equilibrium.…

Symbolic Computation: Parker Edwards, University of Notre Dame, Feature Sizes and Bottlenecks for Algebraic Manifolds

SAS 4201

 In computational topology and geometry, theoretical guarantees for algorithms often take the following form: Start with a finite sample of points from a subspace of . If the sample is "dense enough" with respect to the subspace, then the algorithm outputs a quantity of interest for the subspace, for example its Betti numbers. The quantities associated…

Pure Math Graduate Student Seminar: Kylan Schatz, NC State, Abelian 3-cocycles from Quadratic Forms – Quinn’s Formula

SAS 2235

For some nice subclass of braided monoidal categories, the associator and braiding data are described by an Abelian 3-cocycle . Eilenberg and MacLane demonstrated a surprisingly simple isomorphism between the groups of Abelian 3-cocycles with coefficients in  and quadratic forms with coefficients in , the trace map  by . Like many category theoretical results, this was proven at the level of…

Numerical Analysis: Bao Wang, The University of Utah, Implicit Methods for Deep Learning

Zoom

At the heart of modern deep learning is the deep neural nets accompanied by stochastic optimization and sampling algorithms. These architectures and algorithms have an explicit flavor. In particular, traditional deep nets compose affine and simple nonlinear transformations, defining an explicit function for representation learning. The explicit deep nets lack flexibility and adaptivity for modeling…

SIAM Seminar: Make a Difference – Mathematical Sciences R&D Careers at Sandia National Laboratories

SAS 4201

ake a Difference: Mathematical Sciences R&D Careers at Sandia National Laboratories   R&D Staff from Sandia National Laboratories will be on campus recruiting top NCSU math and statistics students. With sites in NM and CA, SNL is a Department of Energy laboratory conducting wide-ranging science and engineering R&D supporting national security. Please join us for an info session and…

Geometry and Topology Seminar: Ali Feizmohammadi, University of Toronto, Lorentzian Calderón problem under curvature bounds

Zoom

We introduce a method of solving inverse boundary value problems for wave equations on Lorentzian manifolds, and show that zeroth order coefficients can be recovered under certain curvature bounds. The set of Lorentzian metrics satisfying the curvature bounds has a non-empty interior in the sense of smooth, compactly supported perturbations of the metric, whereas all…

Special Event: National Consortium for Data Science (NCDS), Analyzing Data Science Careers

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2022 NCDS Fall Career Panel: Analyzing Data Science Careers | October 19 at 12 PM ET | Virtual Early career professionals and students won’t want to miss these data science professionals provide insight into what it takes to capture the attention of top recruiters in data science and data analytics. Our panelists represent a variety of…

Differential Equations and Nonlinear Analysis Seminar: Michel De Lara, Cermics, École des Ponts ParisTech, France, Hidden Convexity in the l_0 Pseudonorm

Zoom

The so-called $l_0$ pseudonorm counts the number of nonzero components of a vector. It is standard in sparse optimization problems. However, as it is a discontinuous and nonconvex function, the l0 pseudonorm cannot be satisfactorily handled with the Fenchel conjugacy. In this talk, we review a series of recent results on a class of Capra…