Georgia Institute of Technology College of Sciences

Applied algebraic geometry is a subfield of applied mathematics that utilizes concepts, tools, and techniques from algebraic geometry to solve problems in various applied sciences. It blends tools from algebraic geometry, optimization, and statistics to develop certifiable computational algebraic methods to address modern engineeering challenges.

In this talk, I will showcase the power of these methods in solving problems related to Gaussian mixture models (GMMs). In the first part of the talk I will discuss a statistical technique for parameter recovery called the method of moments. I will discuss how to leverage algebraic techniques to design scalable and certifiable moment-based methods for parameter recovery of GMMs. In the second part of this talk, I will discuss recent work relating to Gaussian Voronoi cells. This work introduces new geometric perspectives with implications for high-dimensional data analysis. I will also touch on how these methods complement my broader research in polynomial optimization and power systems engineering.

https://gatech.zoom.us/j/97398944571?pwd=s8S02kNZd5dyVvSY8mZzNOfbNZrqfg.1

Given a modular form $f$, one can construct a measure $\mu_f$ on the modular surface $SL(2,\mathbb{Z})\backslash\mathbb{H}$. The celebrated mass equidistribution theorem of Holowinsky and Soundararajan states that as $k\rightarrow\infty$, the measure $\mu_f$ approaches the uniform measure on the surface. Given a maximal order in a quaternion algebra which is non-split over $\mathbb{Q}$, a maximal order leads to a cocompact subgroup of $R^1\subseteq SL(2,\mathbb{Z})$ where the quotient $R^1\backslash\mathbb{H}$ is a Shimura curve. Given a Hecke form $f$ on this Shimura curve, one can construct the analogous measure $\mu_f$, and ask about the limit as $k\rightarrow\infty$. Recent work of Nelson relates this equidistribution problem for the cocompact case to obtaining bounds on sums of Hecke eigenvalues summed over quadratic progressions. In this talk, I will describe this problem in both the cocompact and non-cocompact case while highlighting how differences in algebras lead to differences in geometry. I will then state progress that I have made on bounds that correspond to square root cancellation on average for sums of Hecke eigenvalues summed over quadratic progressions when averaged over a basis of Hecke forms. 

In this talk, I will present a complete coarse classification of strongly exceptional Legendrian realizations of the connected sum of two Hopf links in contact 3-spheres. This is joint work with Sinem Onaran.

Margulis inequalities and Margulis functions (a.k.a Foster-Lyapunov stability) have played a major role in modern dynamics, in particular in the fields of homogeneous dynamics and Teichmuller dynamics.
Moreover recent exciting developments in the field of random walks over manifolds give rise to related notions and questions in a much larger geometrical content, largely motivated by upcoming work of Brown-Eskin-Filip-Rodriguez Hertz.

I will explain what are Margulis functions and Margulis inequalities and describe the main lemma due to Eskin-Margulis (“uniform expansion”) that allows one to prove such an inequality. I will also try to sketch some interesting applications.

No prior knowledge is needed, the talk will be self-contained and accessible.