Previous Conferences & Workshops

Dec
09
2015

Workshop on Flows, Foliations and Contact Structures

Convex surfaces and grid diagrams
Ivan Dynnikov
2:30pm|Simonyi Hall 101
I will speak about a simple way to represent surfaces in the three-space by diagrams similar to rectangular diagrams of links. A set of moves will be given by which one can connect any two diagrams representing isotopic surfaces. By forbidding some...
Dec
09
2015

Workshop on Flows, Foliations and Contact Structures

Symplectic fillability of contact graph manifolds via line arrangements
Laura Starkston
10:00am|Simonyi Hall 101
An interesting aspect of the classification of symplectic fillings of Seifert fibered spaces is the appearance of complex and symplectic line arrangements in CP2. Line arrangements have been studied classically for decades and have intricate...
Dec
08
2015

Workshop on Flows, Foliations and Contact Structures

Uniqueness of the contact structure approximating a foliation
2:30pm|Simonyi Hall 101
A well known result of Eliashberg and Thurston states that smooth foliations can be approximated by contact structures. We discuss the uniqueness of this contact structure and applications.
Dec
08
2015

Workshop on Flows, Foliations and Contact Structures

Floer homology and covering spaces
11:30am|Simonyi Hall 101
I will discuss a Smith-type inequality for regular covering spaces in monopole Floer homology. Using the monopole Floer / Heegaard Floer correspondence, it follows that if a 3-manifold Y admits a p^n-sheeted regular cover that is a Z/p-L-space (for...
Dec
08
2015

Computer Science/Discrete Mathematics Seminar II

Ramanujan coverings of graphs
10:30am|West Bldg. Lect. Hall

Ramanujan graphs are optimal expander graphs, and their existence and construction have been the focus of much research during the last three decades. We prove that every bipartite Ramanujan graph has a $d$-covering which is also Ramanujan. This...

Dec
08
2015

Workshop on Flows, Foliations and Contact Structures

Quasigeodesic pseudo-Anosov flows in hyperbolic 3-manifolds
10:00am|Simonyi Hall 101
We obtain a simple topological and dynamical systems condition which is necessary and sufficient for an arbitrary pseudo-Anosov flow in a closed, hyperbolic three manifold to be quasigeodesic. Quasigeodesic means that orbits are efficient in...
Dec
07
2015

Workshop on Flows, Foliations and Contact Structures

Tight, non-fillable contact structures on 3-manifolds
Andy Wand
4:00pm|Simonyi Hall 101
The modern development of contact geometry in 3 dimensions has seen several (due to Giroux, Wendl, Latschev and Wendl, Hutchings, and others) invariants of contact structures meant in some sense to measure non-(Stein /symplectic)-fillability of the...
Dec
07
2015

Workshop on Flows, Foliations and Contact Structures

Positive-definite symplectic four-manifolds
2:30pm|Simonyi Hall 101
We give new constraints on the topology of symplectic four-manifolds using invariants from Heegaard Floer homology. In particular, we will prove that certain simply-connected four-manifolds with positive-definite intersection forms cannot admit...