The SGGTC seminar meets on Fridays in Math 520 from 10:3011:30am and in Math 407 from 12pm, unless noted otherwise (in red).
Previous semesters: Fall 2018, Spring 2018, Fall 2017, Spring 2017, Fall 2016, Spring 2016, Fall 2015, Spring 2015, Fall 2014, Spring 2014, Fall 2013, Spring 2013, Fall 2012, Spring 2012, Fall 2011, Spring 2011, Fall 2010, Spring 2010, Fall 2009, Spring 2009, Fall 2008, Spring 2008, Fall 2007.
Our email list.
Date  Speaker  Title 
Feb. 1, 1pm  Florent Schaffhauser (Universidad de Los Andes and Université de Strasbourg) 
Higher Teichmüller spaces for orbifolds 
Feb. 8, 1pm  Siddhi Krishna (Boston College) 
Taut Foliations, Positive 3Braids, and the LSpace Conjecture 
Feb. 15, 10:30am  Marco Castronovo (Rutgers) 
Counting branes on the GelfandCetlin Lagrangian 
Feb. 22, 10:30am  Barney Bramham (IAS and Bochum) 
Orbit travel and symbolic dynamics for 3D Reeb flows using finite energy foliations 
Feb. 22, 1pm  Nate Bottman (IAS) 
Family polyfolds and an Ainfinity structure on the bar construction 
Mar. 1, 10:30am  Du Pei (QGM and Caltech)

TBA 
Mar. 1, 1pm  Yaron Ostrover (IAS and Tel Aviv University) 
TBA 
Mar. 8, 10:30am  Biji Wong (CIRGET, UQaM) 
TBA 
Mar. 8, 1pm  Matt Hedden (Michigan State) 
Satellites of Infinite Rank in the Smooth Concordance Group 
Mar. 15, 10:30am  Ran Tessler (Weizmann Institute) 
TBA 
Mar. 15, 1pm  Nick Saveliev (Miami) 
TBA 
Mar. 22  Spring break! 

Mar. 29, 10:30am  Beibei Liu (UC Davis) 
TBA 
Mar. 29, 1pm  Zhengyi Zhou (IAS) 
TBA 
Apr. 5, 10:30am  Aleksander Doan (Stony Brook) 
TBA 
Apr. 5, 1pm  Alex Takeda (UC Berkeley) 
TBA 
Apr. 12, 10:30am  Jingyu Zhao (Harvard) 
TBA 
Apr. 12, 1pm  Masaki Taniguchi (Tokyo university) 
TBA 
Apr. 19, 10:30am  James Pascaleff (UIUC) 
TBA 
Apr. 19, 1pm  Peter Feller (ETH Zurich) 
TBA 
Apr. 26, 10:30am  Baptiste Chantraine (Université of Nantes) 
TBA 
Apr. 26, 1pm  Jonathan Simone (UMass Amherst) 
TBA 
May 3, 10:30am  Daniel Pomerleano 
TBA 
May 3, 1pm  C.M. Michael Wong (LSU) 
TBA 
Abstracts
February 1st, 2019: Florent Schaffhauser (Universidad de Los Andes and Université de Strasbourg) " Higher Teichmüller spaces for orbifolds "
Abstract: The Teichmüller space of a compact 2orbifold X can be defined as the space of faithful and discrete representations of the fundamental group of X into PGL(2,R). It is a contractible space. For closed orientable surfaces, "Higher analogues" of the Teichmüller space are, by definition, (unions of) connected components of representation varieties of $\pi_1(X)$ that consist entirely of discrete and faithful representations. There are two known families of such spaces, namely Hitchin representations and maximal representations, and conjectures on how to find others. In joint work with Daniele Alessandrini and GyeSeon Lee, we show that the natural generalisation of Hitchin components to the orbifold case yield new examples of Higher Teichmüller spaces: Hitchin representations of orbifold fundamental groups are discrete and faithful, and share many other properties of Hitchin representations of surface groups. However, we also uncover new phenomena, which are specific to the orbifold case.
February 8th, 2019: Siddhi Krishna (Boston College) " Taut Foliations, Positive 3Braids, and the LSpace Conjecture "
Abstract: The LSpace Conjecture is taking the lowdimensional topology community by storm. It aims to relate seemingly distinct Floer homological, algebraic, and geometric properties of a closed 3manifold Y. In particular, it predicts a 3manifold Y isn't "simple" from the perspective of HeegaardFloer homology if and only if Y admits a taut foliation. The reverse implication was proved by Ozsvath and Szabo. In this talk, we'll present a new theorem supporting the forward implication. Namely, we'll build taut foliations for manifolds obtained by surgery on positive 3braid closures. As an example, we'll construct taut foliations in *every* nonLspace obtained by surgery along the P(2,3,7) pretzel knot. No background in HeegaardFloer or foliation theories will be assumed.
February 15th, 2019: Marco Castronovo (Rutgers) " Counting branes on the GelfandCetlin Lagrangian "
Abstract: Starting from Kontsevich's homological mirror symmetry conjecture, derived equivalences between symplectic and algebraic geometry have been intensely investigated, even beyond the CalabiYau setting. In the Fano case, MarshRietsch proposed LandauGinzburg mirrors for the complex Grassmannians Gr(k,n) that fit in a general picture relating mirror symmetry and Langlands duality. We show that a Lagrangian torus fiber of the GelfandCetlin integrable system on Gr(k,n) always supports nonzero objects of the Fukaya category, and for n prime these suffice to generate and establish an equivalence with the category of singularities of the mirror. The arithmetic restriction is curiously related to the values of Schur polynomials at roots of unity.
Februrary 22nd, 2019: Nate Bottman (IAS) " Family polyfolds and an $\mathcal{A}_\infty$ structure on the bar construction "
Abstract: I will describe two areas of recent progress in the construction and study of Symp, the symplectic $(\mathcal{A}_\infty,2)$category. First, I will explain how associating operations to fiber products of 2associahedra gives rise to a coherent algebraic structure, which in particular endows the bar construction $TA[1]$ with an $\mathcal{A}_{\infty}$ structure. This is one way to circumvent the fact that strata of 2associahedra involve fiber products of lowerdimensional 2associahedra. I will also mention a related construction, which exhibits $QC^*$ as a module over a decategorification of Symp. Second, I will present workinprogress with Katrin Wehrheim in which we aim to construct a notion of "family polyfolds". This will be a framework for setting up Fredholm problems that involve adiabatic limits. Our motivating example is the stripshrinking degeneration, which is a key feature of the moduli spaces of pseudoholomorphic quilts involved in the definition of Symp.
February 22th, 2019: Barney Bramham (IAS and Bochum) " Orbit travel and symbolic dynamics for 3D Reeb flows using finite energy foliations "
Abstract: Suppose a nondegenerate Reeb flow of a closed contact 3manifold admits a finite energy foliation F. The rigid leaves in F divide the space into various regions A, B, C etc. A typical Reeb trajectory then spits out an infinite sequence of letters which record which regions it visits and in which order. It is natural to investigate the converse. Indeed, it turns out one needs surprisingly little information to determine, for a given sequence of letters, whether there exists a Reeb trajectory realising this sequence as its itineraries. I will explain this mechanism with pictures and discuss some applications. This is joint work with Umberto Hryniewicz and Gerhard Knieper.
March 8th, 2019: Matt Hedden (Michigan State) " Satellites of Infinite Rank in the Smooth Concordance Group "
Abstract: I'll discuss the way satellite operations act on the concordance group, and raise some questions and conjectures. In particular, I'll conjecture that satellite operations are either constant or have infinite rank, and reduce this to the difficult case of winding number zero satellites. I'll then talk about how to use SO(3) gauge theory to provide a general criterion sufficient for the image of a satellite operation to generate an infinite rank subgroup of smooth concordance, and use this to address the winding zero case. This is joint work with Juanita PinzonCaicedo.
Our email list.
Announcements for this seminar, as well as for related seminars and events, are sent to the "Floer Homology" email list maintained via Google Groups.