- Series
- Geometry Topology Seminar
- Time
- Monday, February 6, 2017 - 2:30pm for 2.5 hours
- Location
- UGA Room 303
- Speaker
- Dan Cristofaro-Gardiner and John Etnyre – Harvard and Georgia Tech
- Organizer
- Caitlin Leverson
John Etnyre: "Embeddings of contact manifolds"
Abstract: I will discuss recent results concerning embeddings and
isotopies of one contact manifold into another. Such embeddings should
be thought of as generalizations of transverse knots in 3-dimensional
contact manifolds (where they have been instrumental in the development
of our understanding of contact geometry). I will mainly focus on
embeddings of contact 3-manifolds into contact 5-manifolds. In this
talk I will discuss joint work with Ryo Furukawa aimed at using braiding
techniques to study contact embeddings. Braided embeddings give an
explicit way to represent some (maybe all) smooth embeddings and should
be useful in computing various invariants. If time permits I will also
discuss other methods for embedding and constructions one may perform on
contact submanifolds.
Dan Cristofaro-Gardiner: "Beyond the Weinstein conjecture"
Abstract: The Weinstein conjecture states that any Reeb vector field
on a closed manifold has at least one closed orbit. The
three-dimensional case of this conjecture was proved by Taubes in 2007,
and Hutchings and I later showed that in this case there are always at
least 2 orbits. While examples exist with exactly two orbits, one
expects that this lower bound can be significantly improved with
additional assumptions. For example, a theorem of Hofer, Wysocki, and
Zehnder states that a generic nondegenerate Reeb vector field associated
to the standard contact structure on $S^3$ has either 2, or infinitely
many, closed orbits. We prove that any nondegenerate Reeb vector field
has 2 or infinitely many closed orbits as long as the associated contact
structure has torsion first Chern class. This is joint work with Mike
Hutchings and Dan Pomerleano.