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Events

Enrique Zuazua, DeustoTech Bilbao and Universidad Autonoma de Madrid, “Control and numerics: recent progress and challenges”

SAS 4201

In most real life applications Mathematics not only face the challenge of modeling (typically by means of ODE and/or PDE), analysis and computer simulations but also the need control and design. And the successful development of the needed computational tools for control and design cannot be achieved by simply superposing the state of the art…

Andrea Arnold, NC State, “Bayesian filtering for time-varying parameter estimation in biological models”

Cox 306

Many applications in the life sciences involve unknown system parameters that must be estimated using little to no prior information. In addition, these parameters may be time-varying and possibly subject to structural characteristics such as periodicity. We show how nonlinear Bayesian filtering techniques can be employed in this setting to estimate unknown, time-varying parameters, while…

Uladzimir Shtukar, NC Central University, “Canonical bases, subalgebras, reductive pairs of Lie algebras, and possible applications”

SAS 4201

Subalgebras of Lie algebra of Lorentz group will be discussed as the basic examples at the beginning of the report. The corresponding analysis is performed by canonical bases for subspaces of a vector space. All canonical bases for 5-dimensional and 4-dimensional subspaces of a 6-dimensional vector space are found, and they are utilized to find…

Christine Mennicke, NC State, “Methods for modeling cell proliferation and differentiation patterns in the neurogenesis-to-gliogenesis switch”

SAS 4201

Radial glial progenitors follow patterns of proliferation and differentiation to produce neurons and glia in the developing brain. The cells first undergo neurogenesis, producing neurons in a fairly deterministic manner, and then a portion of the cell population switches to producing glia. This neurogenesis-to-gliogenesis switch (NGS) and the patterns of cell division in gliogenesis are…

Weekly Brown Bag Lunch

SAS 4104

Please join us for our weekly brown bag lunch! You bring your lunch, and we will bring a delicious treat. Everyone (not just women) is welcome to join or stop by for as long as they can!

Christopher Durden, “Geometry and polynomial invariants of a phylogenetic model”

We will discuss whether it is possible to reconstruct a phylogenetic tree from sequence data, given a specific model of evolution. To answer this question for a coalescent-based model, we study ideals associated to the model. By observing some facts about the geometry of the model, we can demonstrate that these ideals contain polynomials which may…

Arvind Saibaba, NC State, “Matrix CUR decomposition”

SAS 2229

CUR decomposition is a low-rank matrix decomposition that is formed using a small number of actual columns and actual rows of the data matrix. Since this decomposition is explicitly constructed using entries from the actual data set, CUR decomposition may be interpretable by practitioners; for this reason, it is sometimes preferable to the Singular Value…

Seth Sullivant, NC State, “The problem with birthdays”

How many people need to be in a room to guarantee that there is a large probability that a pair of them have the same birthday? The number of people is surprisingly small, a fact that is sometimes called the ”birthday paradox” because it contradicts our intuition. The simple mathematics behind the birthday paradox leads to ”birthday attacks” on cryptographic protocols…

Weekly Brown Bag Lunch

SAS 4104

Please join us for our weekly brown bag lunch! You bring your lunch, and we will bring a delicious treat. Everyone (not just women) is welcome to join or stop by for as long as they can!

Faye Pasley, “Determinantal representations of hyperbolic plane curves with dihedral invariance”

Given a determinantal representation by means of a cyclic weighted shift matrix, one can show the resulting polynomial is hyperbolic and invariant under the action of the dihedral group. Chien and Nakazato (2015) asked the converse question. By properly modifying a determinantal representation construction of Dixon (1902), we show for every hyperbolic polynomial with dihedral…

Jamie Pommersheim, Reed College, “Euler-Maclaurin summation formulas for polytopes”

SAS 4201

Discovered in the 1730s, the classical Euler-Maclaurin formula may be viewed as a formula for summing the values of a function over the lattice points in a one-dimensional polytope. Several years ago, Berline and Vergne generalized this formula to polytopes of arbitrary dimension, obtaining a formula for the sum of a polynomial function over the…

Owen Coss, NC State, “Computing real equilibria of the Kuramoto model “

SAS 4201

The Kuramoto model is used to describe synchronization behavior of a large set of oscillators. The equilibria of this model can be computed by solving a system of polynomial equations using algebraic geometry. Typical methods for solving such polynomial systems compute all complex equilibrium points when only the real equilibrium points are of physical interest,…