Talk_id  Date  Speaker  Title 
18593

Thursday 8/29 2:00 PM

Chris Gerig, Harvard University

Probing 4manifolds with nearsymplectic forms
 Chris Gerig, Harvard University
 Probing 4manifolds with nearsymplectic forms
 08/29/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
Most closed 4manifolds do not admit symplectic forms, but most admit "nearsymplectic forms", certain closed 2forms which are symplectic outside of a collection of circles. This provides a gateway from the symplectic world to the nonsymplectic world. I will first briefly sketch a geometric interpretation of the SeibergWitten invariants in terms of Jholomorphic curves that are compatible with the nearsymplectic form. Although the SeibergWitten invariants don't apply to (potentially exotic) 4spheres, nor do these spheres admit nearsymplectic forms, there is still a way to bring in nearsymplectic techniques.

19602

Thursday 9/5 2:00 PM

Alex Waldron, Michigan State University

$G_2$instantons on the 7sphere
 Alex Waldron, Michigan State University
 $G_2$instantons on the 7sphere
 09/05/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
I'll discuss a forthcoming paper studying families of $G_2$instantons on $S^7$, focusing on those which are obtained by pulling back asd instantons on $S^4 $ via the quaternionic Hopf fibration. In the charge1 case this yields a smooth and complete 15dimensional family. The situation for higher charge is more complicated, but we are able to compute all the infinitesimal deformations.

19635

Thursday 9/12 2:00 PM

Honghao Gao, MSU

Augmentations and sheaves for links
 Honghao Gao, MSU
 Augmentations and sheaves for links
 09/12/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
We study two different invariants of framed oriented links. Augmentations are rank one representations of a noncommutative algebra, whose definition is motivated by Floer homology. Sheaves in microlocal theory can be thought of as generalizations of link group representations. We will demonstrate two constructions going back and forth between these invariants. We will also tell a motivating story behind the scene, using SFT and microlocalization correspondence in symplectic topology.

19621

Thursday 9/19 2:00 PM

Shelly Harvey, Rice

TBA
 Shelly Harvey, Rice
 TBA
 09/19/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
TBA

18580

Thursday 9/26 2:00 PM

David Boozer, UCLA

Holonomy perturbations of the ChernSimons functional for lens spaces
 David Boozer, UCLA
 Holonomy perturbations of the ChernSimons functional for lens spaces
 09/26/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
We describe a scheme for constructing generating sets for Kronheimer and Mrowka's singular instanton knot homology for the case of knots in lens spaces. The scheme involves Heegaardsplitting a lens space containing a knot into two solid tori. One solid torus contains a portion of the knot consisting of an unknotted arc, as well as holonomy perturbations of the ChernSimons functional used to define the homology theory. The other solid torus contains the remainder of the knot. The Heegaard splitting yields a pair of Lagrangians in the traceless $SU(2)$character variety of the twicepunctured torus, and the intersection points of these Lagrangians comprise the generating set that we seek. We illustrate the scheme by constructing generating sets for several example knots. Our scheme is a direct generalization of a scheme introduced by Hedden, Herald, and Kirk for describing generating sets for knots in $S^3$ in terms of Lagrangian intersections in the traceless $SU(2)$character variety for the 2sphere with four punctures.

18586

Thursday 10/3 2:00 PM

Rita Gitik, Michigan

On Geodesic Triangles in the Hyperbolic Plane
 Rita Gitik, Michigan
 On Geodesic Triangles in the Hyperbolic Plane
 10/03/2019
 2:00 PM  2:50 PM
 C304 Wells Hall
Let M be an orientable hyperbolic surface without boundary and
let c be a closed geodesic in M. We prove that any side of any triangle formed by distinct lifts of c in the hyperbolic plane is shorter than c.

19632

Thursday 10/17 2:00 PM

Jesse Madnick , McMaster University

TBD
 Jesse Madnick , McMaster University
 TBD
 10/17/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
No abstract available.

19641

Thursday 10/24 2:00 PM

Lev TovstopyatNelip, MSU

TBA
 Lev TovstopyatNelip, MSU
 TBA
 10/24/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
No abstract available.

19619

Thursday 10/31 2:00 PM

Boyu Zhang, Princeton University

TBD
 Boyu Zhang, Princeton University
 TBD
 10/31/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
No abstract available.

19622

Thursday 11/14 2:00 PM

Peter LambertCole, Max Planck Institute for Mathematics

TBA
 Peter LambertCole, Max Planck Institute for Mathematics
 TBA
 11/14/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
TBA

19628

Thursday 11/21 2:00 PM

Akram Alishahi, University of Georgia

TBA
 Akram Alishahi, University of Georgia
 TBA
 11/21/2019
 2:00 PM  3:00 PM
 C304 Wells Hall
TBA
