Talk_id  Date  Speaker  Title 
4073

Thursday 9/7 2:00 PM

Mark Greenfield, University of Michigan

Thurston's metric on Teichmueller spaces of flat ntori
 Thurston's metric on Teichmueller spaces of flat ntori
 09/07/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Mark Greenfield, University of Michigan
Several interesting metrics have been defined for Teichmueller spaces of hyperbolic surfaces. However, analogous metrics on the Teichmueller space of flat ntori have not been as well studied. After reviewing some background on Teichmueller theory, we will define an analog of Thurston's metric for these spaces. We find that in dimension n=2, it agrees with the hyperbolic metric. In particular, this gives a new way to realize the hyperbolic plane as the moduli space of marked flat tori. Time permitting, we will describe the corresponding situation in dimension n>2. This work is joint with Lizhen Ji.

4102

Thursday 9/14 2:00 PM

Diana Hubbard, University of Michigan

On the braid index and the fractional Dehn twist coefficient
 On the braid index and the fractional Dehn twist coefficient
 09/14/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Diana Hubbard, University of Michigan
The braid index of a knot is the least number of strands necessary to represent the knot as a closure of a braid on that many strands. If we view a braid as an element of the mapping class group of the punctured disk, its fractional Dehn twist coefficient (FDTC) is a number that measures the amount of twisting it exerts about the boundary of the disk. In this talk I will demonstrate that nbraids with FDTC larger than n1 realize the braid index of their closure. The proof uses the concordance homomorphism Upsilon arising from knot Floer homology as a crucial tool. This is joint work with Peter Feller.

4089

Thursday 9/21 2:00 PM

Adam Jacob, UC Davis

The deformed HermitianYangMills equation
 The deformed HermitianYangMills equation
 09/21/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Adam Jacob, UC Davis
In this talk I will discuss a complex generalization of the special Lagrangian graph equation of HarveyLawson. I will discuss methods for constructing solutions, and relate the solvability of the equation with notions of stability from symplectic and algebraic geometry. This is joint work with T.C. Collins and S.T. Yau.

4105

Thursday 9/28 2:00 PM

Renaud Detcherry, MSU

Turaev Viro invariants and Gromov norm
 Turaev Viro invariants and Gromov norm
 09/28/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Renaud Detcherry, MSU
According to Chen and Yang's volume conjecture, the asymptotics of the TuraevViro invariants of a 3manifold predicts its hyperbolic volume. We show a compatibility between TuraevViro invariants and JSJdecomposition and get an ineqality relating TuraevViro invariants and Gromov norm.

4124

Thursday 10/5 2:00 PM

Thomas Walpuski, MSU

Wallcrossing for the SeibergWitten equation with two spinors
 Wallcrossing for the SeibergWitten equation with two spinors
 10/05/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Thomas Walpuski, MSU
Unlike for the classical SeibergWitten equation, compactness fails for the SeibergWitten equation with multiple spinors. This noncompactness is caused by Fueter sections with values in the moduli space of charge 1 SU(n) ASD instantons. In the simplest case, n = 2, those are Z/2 harmonic spinors. In this talk I will explain in more detail what the preceding sentences mean and then discuss the wallcrossing caused by the appearance of (nonsingular) Z/2 harmonic spinors. Time permitting, I will discuss how our wallcrossing formulae can be used to prove the existence of singular Fueter sections.
This is joint work with Aleksander Doan.

5159

Thursday 10/12 2:00 PM

Wenzhao Chen, MSU

A lower bound for the double slice genus
 A lower bound for the double slice genus
 10/12/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Wenzhao Chen, MSU
Every knot in the 3sphere can be realized as a crosssection of some unknotted surface in the 4sphere. For a given knot, the least genus of any of such surface is defined to be its double slice genus. Obviously twice the slice genus of a knot is a lower bound for its double slice genus. One really basic question is whether the double slice genus can be arbitrarily large compared to twice the slice genus. However, this was not answered due to the lack of lower bounds for the double slice genus. In this talk I will introduce a lower bound that can be used to answer this question.

4115

Thursday 10/19 2:00 PM

Elmas Irmak, Bowling Green State University

Simplicial Maps of Complexes of Curves and Mapping Class Groups of Surfaces
 Simplicial Maps of Complexes of Curves and Mapping Class Groups of Surfaces
 10/19/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Elmas Irmak, Bowling Green State University
I will talk about recent developments on simplicial maps of complexes of curves on both orientable and nonorientable surfaces. I will also talk about joint work with Prof. Luis Paris. We prove that on a compact, connected, nonorientable surface of genus at least 5, any superinjective simplicial map from the twosided curve complex to itself is induced by a homeomorphism that is unique up to isotopy. As an application we give classification of injective homomorphisms from finite index subgroups of the mapping class group to the whole group.

5128

Thursday 11/2 2:00 PM

Meera Mainkar, Central Michigan University (Visiting MSU this term)

Meera Mainkar
 Meera Mainkar
 11/02/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Meera Mainkar, Central Michigan University (Visiting MSU this term)
TBA

5143

Thursday 11/9 2:00 PM

Bert Guillou, University of Kentucky

TBA
 TBA
 11/09/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Bert Guillou, University of Kentucky
No abstract available.

4120

Thursday 11/16 2:00 PM

Elizabeth Munch, MSU

TBA
 TBA
 11/16/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 Elizabeth Munch, MSU
No abstract available.

5131

Thursday 11/23 2:00 PM


ThanksgivingNo seminar
 ThanksgivingNo seminar
 11/23/2017
 2:00 PM  3:00 PM
 C304 Wells Hall

No abstract available.

5129

Thursday 11/30 2:00 PM

J.D. Quigley, University of Notre Dame

TBA
 TBA
 11/30/2017
 2:00 PM  3:00 PM
 C304 Wells Hall
 J.D. Quigley, University of Notre Dame
No abstract available.
