## Upcoming Events

## September 2019

## Emily Gunawan, University of Connecticut, Cambrian combinatorics on quiver representations

Let Q be an orientation of a type A Dynkin diagram. An eta map corresponding to Q is a surjection from the weak order on permutations to a Cambrian lattice (of triangulations of a polygon). We give a new geometric way…

Find out more## October 2019

## Donald Sheehy, NC State, On the Cohomology of Impossible Figures, Revisited

The Penrose triangle, also known as the impossible tribar is an icon for cohomology. It is literally the icon for Cech cohomology on Wikipedia. The idea goes back to a paper by Roger Penrose in 1992, but was first reported…

Find out more## Jon Stallrich, NC State, Sign-Informative Design and Analysis of Supersaturated Designs

Much of the literature on the design and analysis of supersaturated designs (SSDs), in which the number of factors exceeds the number of runs, rests on design principles assuming a least-squares analysis. More recently, researchers have discovered the potential of analyzing SSDs with penalized…

Find out more## John Lagergren, SIAM Student Chapter: Graduate Student Tutorial

Machine learning has become widely popular in fields like computer vision, natural language processing, and speech recognition, often performing tasks better than humans. A fundamental building block of many of these algorithms is a neural network known as a multilayer perceptron. In this…

Find out more## 130th Math Department Anniversary Celebration

Register now for a weekend anniversary celebration marking 130 years of mathematics education and research here at NC State. The history of mathematics at the university dates to 1889, when math courses were among the first taught as NC State…

Find out more## Yan Zhuang, Davidson College, Counting permutations by peaks, descents, and cycle type

We present a general formula describing the joint distribution of two permutation statistics—the peak number and the descent number—over any set of permutations whose quasisymmetric generating function is a symmetric function. Our formula involves a certain kind of plethystic substitution…

Find out more## JungHwan Park, Georgia Tech, Rational cobordisms and integral homology

We prove that every rational homology cobordism class in the subgroup generated by lens spaces is represented by a unique connected sum of lens spaces whose first homology embeds in any other element in the same class. As an application,…

Find out more## Eric Hallman, NC State, Sharp 2-norm Error Bounds for LSQR and the Conjugate Gradient Method

When running any iterative algorithm it is useful to know when to stop. Here we review LSQR and LSLQ, two iterative methods for solving \min_x \|Ax-b\|_2 based on the Golub-Kahan bidiagonalization process, as well as estimates for the 2-norm error…

Find out more## Mikhail Klibanov, UNC Charlotte, Carleman Estimates for Globally Convergent Numerical Methods for Coefficient Inverse Problems

The ill-posedness and nonlinearity are two factors causing the phenomenon of multiple local minima and ravines of conventional least squares cost functionals for Coefficient Inverse Problems. Since any minimization method can stop at any point of a local minimum, then…

Find out more## Mike Thompson, Managing Director and CEO of First Analytics, “Mathematics in Industry” Seminar

Mike Thompson, the Managing Director and CEO of First Analytics, will be giving a seminar on how machine learning and mathematics are used to handle large data analytics programs at First Analytics.

Find out more## Mohammad Farazmand, NC State, Extreme Events in Chaos

Chaos refers to seemingly random and unpredictable dynamics of a system that evolves in time. Certain chaotic systems exhibit an additional level of complexity: intermittent extreme events that are noticeably distinct from the usual chaotic dynamics. These extreme events include ocean…

Find out more## Arvind Krishna Saibaba, NC State, The Mathematics Behind Imaging

From x-ray machines to luggage scanners, our lives depend on imaging devices that let us “see” what is impossible to observe with the naked eye. I will explain some of the mathematical ideas that make image reconstructions possible. Along the…

Find out more## Research Statements and CVs

An afternoon workshop/discussion lead by Ilse Ipsen on preparing your research statements and CVs for the job search.

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