Seminars and Colloquia by Series

Monday, January 14, 2013 - 14:05 , Location: Skiles 006 , Dan Margalit , Georgia Institute of Technology , Organizer: Dan Margalit
We give a simple generating set for the following three closely related groups: the hypereliptic Torelli group, the kernel of the integral Burau representation, and the fundamental group of the branch locus of the period mapping.  Our theorem confirms a conjecture of Hain.  This is joint work with Tara Brendle and Andy Putman.
Monday, December 10, 2012 - 14:05 , Location: Skiles 006 , Stavros Garoufalidis , Georgia Tech , , Organizer: Stavros Garoufalidis
I will explain how to construct a 4-variable knot invariant which expresses a recursion for the colored HOMFLY polynomial of a knot, and its implications on (a) asymptotics (b) the SL2 character variety of the knot (c) mirror symmetry.
Monday, November 26, 2012 - 14:00 , Location: Skiles 006 , Ali Maalaoui , Rutgers University , Organizer: John Etnyre
In this talk we are going to present a theorem that can be seen as related to S. Smale's theorem on the topology of the space of Legendrian loops. The framework will be slightly different and the space of Legendrian curves will be replaced by a smaller space $C_{\beta}$, that appears to be convenient in some variational problems in contact form geometry. We will also talk about the applications and the possible extensions of this result. This is a joint work with V. Martino.
Monday, November 19, 2012 - 14:00 , Location: Skiles 006 , Ramon Vera , Durham University , Organizer: John Etnyre
We discuss two concepts of low-dimensional topology in higher dimensions: near-symplectic manifolds and overtwisted contact structures. We present a generalization of near-symplectic 4-manifolds to dimension 6. By near-symplectic, we understand a closed 2-form that is symplectic outside a small submanifold where it degenerates. This approach uses some singular mappings called generalized broken Lefschetz fibrations. An application of this setting appears in contact topology. We find that a contact 5-manifold, which appears naturally in this context, is PS-overtwisted. This property can be detected in a rather simple way.
Monday, November 12, 2012 - 14:00 , Location: Skiles 006 , Youlin Li , Shanghai Jiaotong University and Ga Tech , Organizer: John Etnyre
We classify the Legendrian torus knots in S1XS2 with tight contact structure up to isotopy. This is a joint work with Feifei Chen and Fan Ding.
Monday, October 29, 2012 - 14:00 , Location: Skiles 006 , Yankı Lekili , University of Cambridge & Simons Center , Organizer: John Etnyre
We study some finite quotients of the A_n Milnor fibre which coincide with the Stein surfaces that appear in Fintushel and Stern's rational blowdown construction. We show that these Stein surfaces have no exact Lagrangian submanifolds by using the already available and deep understanding of the Fukaya category of the A_n Milnor fibre coming from homological mirror symmetry. On the contrary, we find Floer theoretically essential monotone Lagrangian tori, finitely covered by the monotone tori that we studied in the A_n Milnor fibre. We conclude that these Stein surfaces have non-vanishing symplectic cohomology. This is joint work with M. Maydanskiy.
Wednesday, October 24, 2012 - 14:00 , Location: Skiles 006 , Tetsuya Ito , UBC , Organizer: John Etnyre
We will give an overview of open book foliation method by emphasizing the aspect that it is a generalization of Birman-Menasco's braid foliation theory. We explain how surfaces in open book reflects topology and (contact) geometry of underlying 3-manifolds, and will give several applications. This talk is based on joint work with Keiko Kawamuro.
Monday, October 15, 2012 - 14:00 , Location: Skiles 006 , none , none , Organizer: John Etnyre
Monday, October 8, 2012 - 14:05 , Location: Skiles 006 , Rodrigo Montes , Univerity of Curitiba, Brazil , , Organizer: Mohammad Ghomi
 In this talk we introduce the notions of the  contact angle and of the holomorphic angle for  immersed surfaces in $S^{2n+1}$.  We deduce formulas for the Laplacian and for the Gaussian curvature, and we will classify minimal surfaces in $S^5$   with the two angles constant. This classification gives a 2-parameter family of minimal flat  tori  of $S^5$. Also, we will  give an alternative proof of the classification of minimal Legendrian surfaces in $S^5$ with constant Gaussian curvature. Finally, we will show some remarks and generalizations  of this classification.    
Monday, October 1, 2012 - 14:00 , Location: Skiles 006 , Keiko Kawamuro , University of Iowa , Organizer: John Etnyre
The fractional Dehn twist coefficient (FDTC), defined by Honda-Kazez-Matic, is an invariant of mapping classes. In this talk we study properties of FDTC by using open book foliation method, then obtain results in geometry and contact geometry of the open-book-manifold of a mapping class. This is joint work with Tetsuya Ito.