Georgia Institute of Technology College of Sciences

In this talk, we introduce contact invariants in bordered sutured Floer homology. Given a contact 3-manifold with convex boundary, we apply a result of Zarev to derive contact invariants in the bordered sutured modules BSA and BSD. We show that these invariants satisfy a pairing theorem, which is a bordered extension of the Honda-Kazez-Matic gluing map for sutured Floer homology. We also show that there is a correspondence between certain A-infinity operations in bordered modules and bypass attachment maps in sutured Floer homology. As an application, we characterize the Stipsicz-Vertesi map in terms of A-infinity action on CFA. If time permits, we will further discuss applications to contact surgery.

Geometric mechanics is a tool for mathematically modeling the locomotion of animals or robots. In this talk I will focus on modeling the locomotion of a very simple robot. This modeling involves constructing a principal SE(2)-bundle with a connection. Within this bundle, the base space is parametrized by variables that are under the control of the robot (the so-called control variables). A loop in the base space gives rise to some holonomy in the fiber, which is an element of the group SE(2). We interpret this holonomy as the locomotion that is realized when the robot executes the path in the base space (control) variables.

Now, we can put a metric on the base space and ask the following natural question: What is the shortest path in the base space that gives rise to a fixed amount of locomotion? This is an extension of the isoperimetric problem to a principal bundle with a connection.

In this talk I will describe how to compute holonomy of the simple robot model, described above. Then I will solve the isoperimetric problem to find the shortest path with a fixed holonomy.

No prior knowledge of geometric mechanics will be assumed for this talk.

The four color theorem states that each bridgeless trivalent planar graph has a proper 4-face coloring. It can be generalized to certain types of CW complexes of any closed surface for any number of colors, i.e., one looks for a coloring of the 2-cells (faces) of the complex with m colors so that whenever two 2-cells are adjacent to a 1-cell (edge), they are labeled different colors.

In this talk, I show how to categorify the m-color polynomial of a surface with a CW complex. This polynomial is based upon Roger Penrose’s seminal 1971 paper on abstract tensor systems and can be thought of as the ``Jones polynomial’’ for CW complexes. The homology theory that results from this categorification is called the bigraded m-color homology and is based upon a topological quantum field theory (that will be suppressed from this talk due to time). The construction of this homology shares some similar features to the construction of Khovanov homology—it has a hypercube of states, multiplication and comultiplication maps, etc. Most importantly, the homology is the $E_1$-page of a spectral sequence whose $E_\infty$-page has a basis that can be identified with proper m-face colorings, that is, each successive page of the sequence provides better approximations of m-face colorings than the last. Since it can be shown that the $E_1$-page is never zero, it is safe to say that a non-computer-based proof of the four color theorem resides in studying this spectral sequence! (This is joint work with Ben McCarty.)

The Poincaré metric on the unit disc $\mathbb{D} \subset \mathbb{C}$, known for its invariance under all biholomorphisms (bijective holomorphic maps) of $\mathbb{D}$, is one of the most fundamental Riemannian metrics in differential geometry.

In this presentation, we will first introduce the Bergman metric on a bounded domain in $\mathbb{C}^n$, which can be viewed as a generalization of the Poincaré metric. We will then explore some key theorems that illustrate how the curvature of the Bergman metric characterizes bounded domains in $\mathbb{C}^n$ and more generally, complex manifolds. Finally, I will discuss my recent work related to these concepts.