## Seminars and Colloquia by Series

Wednesday, February 22, 2017 - 12:00 , Location: Skiles 006 , Hua Xu , Gimmie Games , Organizer: Timothy Duff
In this talk, we will have an overview of: the Gaming Industry, specifically on the Video Slot Machine segment; the top manufactures in the world; the game design studio Gimmie Games, who we are, what we do; what is the process of making a video slot game; what is the basic structure of the math model of a slot game; current strong math models in the market; what is the roll of a game designer in the game development process; the skill set needed to be a successful Game Designer. Only basic probability knowledge is required for this talk.
Wednesday, January 18, 2017 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
On the two-dimensional square grid, remove each nearest-neighbor edge independently with probability 1/2 and consider the graph induced by the remaining edges. What is the structure of its connected components? It is a famous theorem of Kesten that 1/2 is the critical value.'' In other words, if we remove edges with probability p \in [0,1], then for p < 1/2, there is an infinite component remaining, and for p > 1/2, there is no infinite component remaining. We will describe some of the differences in these phases in terms of crossings of large boxes: for p < 1/2, there are relatively straight crossings of large boxes, for p = 1/2, there are crossings, but they are very circuitous, and for p > 1/2, there are no crossings.
Wednesday, November 30, 2016 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
I will start with a brief presentation of the Probability activities in SOM. I will continue by presenting results obtained in SOM, over the past ten years, answering long standing questions insequences comparison.
Wednesday, November 16, 2016 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
A matroid is a combinatorial abstraction of an independence structure, such as linear independence among vectors and cycle-free-ness among edges of a graph.  An algebraic variety is a solution set of a system of polynomial equations, and it has a polyhedral shadow called a tropical variety.  An irreducible algebraic variety gives rise to a matroid via algebraic independence in its coordinate ring.  In this talk I will show that the tropical variety is compatible with the algebraic matroid structure.  I will also discuss some open problems on algebraic matroids and how they behave under operations on tropical varieties.
Wednesday, November 9, 2016 - 12:00 , Location: Skiles 006 , Jonathan Paprocki , Georgia Institute of Technology , Organizer: Timothy Duff
Quantum topology is a collection of ideas and techniques for studying knots and manifolds using ideas coming from quantum mechanics and quantum field theory. We present a gentle introduction to this topic via Kauffman bracket skein algebras of surfaces, an algebraic object that relates "quantum information" about knots embedded in the surface to the representation theory of the fundamental group of the surface. In general, skein algebras are difficult to compute. We associate to every triangulation of the surface a simple algebra called a "quantum torus" into which the skein algebra embeds. In joint work with Thang Le, we make use of this embedding to give a simple proof of a difficult theorem.
Wednesday, November 2, 2016 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
If Google Scholar gives you everything you want, what could Georgia Tech Library possibly do for you? Come learn how to better leverage the tools you know and discover some resources you may not. Get to know your tireless Math Librarian and figure out how to navigate the changes coming with Library Next. This is also an opportunity to have a voice in the Library’s future, so bring ideas for discussion. Refreshments will be served.
Wednesday, October 26, 2016 - 12:00 , Location: Skiles 006 , , Georgia Institute of Technology , Organizer: Timothy Duff
A matrix completion problem starts with a partially specified matrix, where some entries are known and some are not. The goal is to find the unknown entries (“complete the matrix”) in such a way that the full matrix satisfies certain properties. We will mostly be interested in completing a partially specified symmetric matrix to a full positive semidefinite matrix. I will give some motivating examples and then explain connections to nonnegative polynomials and sums of squares.
Wednesday, October 19, 2016 - 12:05 , Location: Skiles 006 , , Department of Mathematics, Georgia Institute of Technology , , Organizer:

Refreshments will be provided before the seminar.

Collective behavior can be seen in many animal species, such as flocking birds, herding mammals, and swarming bacteria. In the continuum limit, these phenomena can be modeled by nonlocal PDEs. In this talk, after discussing some PDE models for collective dynamics, I will focus on the analysis of the Keller-Segel equation, which models bacterial chemotaxis. Mathematically, this equation exhibits an intriguing "critical mass phenomenon": namely, solutions exist globally in time for all initial data whose mass is below some certain constant, whereas finite-time blow-up always happen if the initial mass is above this constant. I will introduce some useful analysis tools that lead to this result, and discuss some active areas of current research.
Wednesday, October 12, 2016 - 12:00 , Location: Skiles 006 , , Department of Mathematics, Georgia Institute of Technology , , Organizer:

Refreshments will be provided before the seminar.

It's important to have a personal academic webpage—one that is up-to-date, informative, and easy to navigate. This workshop will be a hands-on guide to making an academic webpage and hosting it on the School of Math website. Webpage templates will be provided. Please bring a laptop if you have one, as well as a photograph of yourself for your new website. Come and get the help you need to create a great webpage!
Wednesday, October 5, 2016 - 12:00 , Location: Skiles 006 , , Department of Mathematics, Georgia Institute of Technology , , Organizer:

Food and Drinks will be provided before the seminar.

For every surface (sphere, torus, etc.) there is an associated graph called the curve graph.  The vertices are curves in the surface and two vertices are connected by an edge if the curves are disjoint.  The curve graph turns out to be very important in the study of surfaces.  Even though it is well-studied, it is quite mysterious.  Here are two sample problems: If you draw two curves on a surface, how far apart are they as edges of the curve graph? If I hand you a surface, can you draw two curves that have distance bigger than three?  We'll start from the beginning and discuss these problems and some related computational problems on surfaces.