Events
Differential Equations and Nonlinear Analysis Seminar: Yulong Lu, Duke University, Understanding and accelerating statistical sampling algorithms: a PDE perspective
A fundamental problem in Bayesian inference and statistical machine learning is to efficiently sample from probability distributions. Standard Markov chain Monte Carlo methods could be prohibitively expensive due to various complexities of the target distribution, such as multimodality, high dimensionality, large datesets, etc. To improve the sampling efficiency, several new interesting ideas/methods have recently been proposed in the community…
Ricky Liu, NC State, RSKy Business
SAS 2102The Robinson-Schensted-Knuth (RSK) correspondence is an important combinatorial bijection that associates to any permutation a pair of objects called standard Young tableaux. We will describe this correspondence in detail and discuss some interesting connections to combinatorics, algebra, and geometry. This talk will assume no background and will be accessible to all undergraduates.
Pratik Misra, NC State, Bounds on the expected size of the maximum agreement subtree
Rooted binary trees are used in evolutionary biology to represent the evolution of a set of species where the leaves denote the existing species and the internal nodes denote the unknown ancestors. Maximum agreement subtree is used as a measure of discrepancy between two trees. In this talk, I will define the notion of "maximum…
Jean-Pierre Fouque, University of California Santa Barbara, Stochastic Games with Delay: a Toy Model
Park Shops 200Motivated by modeling borrowing and lending between banks, we start by illustrating systemic risk with a toy model of diffusions processes coupled through their drifts. We then show that such a simplistic model is in fact a Nash equilibrium of a Linear-Quadratic differential game. In order to take into account clearing debt obligations a delay…
Meet the Staff
All of the math department staff relevant for graduate students will be here to tell you what they do and answer your pressing questions.
Pedro Aceves Sanchez, NC State, Emergence of Vascular Networks
he emergence of vascular networks is a long-standing problem which has been the subject of intense research in the past decades. One of the main reasons being the widespread applications that it has in tissue regeneration, wound healing, cancer treatment, etc. The mechanisms involved in the formation of vascular networks are complex and despite the vast amount of research devoted to it, there are still…
Tea and Cookies
SAS 4104Nathan Reading, NC State, Regular Polytopes and Tessellations: Why life is more interesting in low dimension
SAS 2102Polytopes (also known in dimensions zero through three as "points", "line segments", “polygons", and “polyhedra") have been objects of interest to mathematicians throughout the recorded history of mathematics. Most notably, the five Platonic solids were probably known at least a thousand years before Plato. Regular polytopes are "as symmetric as possible" in a sense that…
Christian Smith, NC State, The Algebra of “up-operators” for Young’s Lattice and Bruhat Order on S_n
Let be a free associative algebra over generated by for in some indexing set and let be a poset. For and we define an action of on (the complex vector space with basis ) in a way such that either annihilates or sends it to where covers and we extend multiplicatively and linearly. Let be the two-sided ideal which annihilates all elements of . We characterize when is Young's Lattice and we discuss the…
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 to construct the Auslander-Reiten quiver of the quiver representations rep(Q). We use it to naturally define…
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 by Penrose several years earlier. There, he shows how the impossibility of the figure depends…
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 regression methods like the LASSO and Dantzig selector estimators. There exists much theoretical work for these methods…
AWM Brown Bag Lunch
SAS 4104Tea and Cookies
SAS 4104John Lagergren, SIAM Student Chapter: Graduate Student Tutorial
Mann 404Machine 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 tutorial we will discuss how to construct these networks and how to train them using back propagation…
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 ushered in its inaugural class of students. Harrelson Hall was the former home of the…