# Mathematics Department

Last updated: 2019/01/21 - 2:19pm

#### Mixing times and the cutoff phenomenon.

##### Evita Nestoridi (Princeton University)
Monday, January 21 - 12:00 pm
119 Physics

Markov chains are random processes that retain no memory of the past. The mixing time of a Markov chain is the time it takes for it to reach equilibrium. During the last three decades, there has been...

#### Gauge theory on Aloff-Wallach spaces

##### Gonçalo Oliveira (Universidade Federal Fluminense, GMA-Instítuto de Matemática)
Tuesday, January 22 - 3:15 pm
119 Physics

I will describe joint work with Gavin Ball where we classify certain G2-Instantons on Aloff-Wallach spaces. This classification can be used to test ideas and explicitly observe various interesting...

#### Large deviations for sparse random graphs

##### Nicholas Cook
Wednesday, January 23 - 12:00 pm
119 Physics

Let $G=G(N,p)$ be an Erd\H{o}s--R\'enyi graph on $N$ vertices (where each pair is connected by an edge independently with probability $p$). We view $N$ as going to infinity, with $p$ possibly going to...

#### Data Dialogue

##### Ytzachak Solomon (Brown University Math Dept.)
Thursday, January 24 - 11:45 am
Gross Hall, Ahmadieh Family Grand Hall, Room 330

Lunch: 11:45 am Seminar: Noon

#### Chaotic regimes for random dynamical systems

##### Alex Blumenthal (University of Maryland, Mathematics)
Thursday, January 24 - 3:15 pm
119 Physics

It is anticipated that chaotic regimes (e.g., strange attractors) arise in a wide variety of dynamical systems, including those arising from the study of ensembles of gas particles and fluid mechanics...

#### Algorithms for stochastic nonconvex and nonsmooth optimization

##### Courtney Paquette (University of Waterloo)
Friday, January 25 - 12:00 pm
119 Physics

Nonsmooth and nonconvex loss functions are often used to model physical phenomena, provide robustness, and improve stability. While convergence guarantees in the smooth, convex settings are well-...

#### Harnessing environmental surveillance: mathematical modeling in the fight against polio

##### Andrew Brouwer (University of Michigan)
Friday, January 25 - 1:30 pm
119 Physics

Israel experienced an outbreak of wild poliovirus type 1 (WPV1) in 2013-14, detected through environmental surveillance of the sewage system. No cases of acute flaccid paralysis were reported, and the...

#### TBA

##### Jim Nolen
Monday, January 28 - 12:00 pm
119 Physics

#### Gradient Boosting Machines: Structural Insights and Improved Algorithms

##### Haihao Lu (MIT)
Monday, January 28 - 12:00 pm
LSRC D106

The gradient boosting machine (GBM) is one of the most successful supervised learning algorithms, and it has been the dominant method in many data science competitions, including Kaggle and KDDCup. In...

#### Extremal primes for elliptic curves without complex multiplication

##### Ayla Gafni (University of Rochester)
Wednesday, January 30 - 3:15 pm
119 Physics

Fix an elliptic curve $E$ over $\mathbb{Q}$. An ''extremal prime'' for $E$ is a prime $p$ of good reduction such that the number of rational points on $E$ modulo $p$ is maximal or minimal in relation...