Other area seminars. Our e-mail list. Archive of previous semesters
Fall 2021
| Date | Time (Eastern) | Speaker | Title |
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September 17 |
11 am (Note nonstandard time) |
Proper actions of 3-manifold groups on finite product of quasi-trees |
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September 24 |
2 pm |
The Khovanov homology of slice disks |
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October 1 |
2 pm |
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October 8 |
2 pm |
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October 15 |
2 pm |
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October 22 |
2 pm |
Jonathan Zung |
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October 29 |
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November 5 |
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November 12 |
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November 19 |
2 pm |
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December 3 |
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December 10 |
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Abstracts
Wenyuan Yang, Peking University
Title: Proper actions of 3-manifold groups on finite product of quasi-trees
Abstract: Let M be a compact, connected, orientable 3-manifold. In this talk, I will study when the fundamental group of M acts properly on a finite product of quasi-trees. Our main result is that this is so exactly when M does not contain Sol and Nil geometries. In addition, if there is no $\widetilde{SL(2, \mathbb{R})}$ geometry either, then the orbital map is a quasi-isometric embedding of $\pi_1(M)$. This is called property (QT) by Bestvina-Bromberg-Fujiwara, who established it for residually finite hyperbolic groups and mapping class groups. The main step of our proof is to show property (QT) for the classes of Croke-Kleiner admissible groups and of relatively hyperbolic groups under natural assumptions. Accordingly, this yields that graph 3-manifold and mixed 3-manifold groups have property (QT). This represents joint work with N.T. Nguyen and S.Z. Han.
Isaac Sundberg, Bryn Mawr College
Title: The Khovanov homology of slice disks
Abstract: A smooth, oriented surface that is properly embedded in the 4-ball can be regarded as a cobordism between the links it bounds, namely, the empty link and its boundary in the 3-sphere. To such link cobordisms, there is an associated linear map between the Khovanov homology groups of the boundary links, and moreover, these maps are invariant, up to sign, under boundary-preserving isotopy of the surface. In this talk, we review these maps and use their invariance to understand the existence and uniqueness of slice disks and other surfaces in the 4-ball. This reflects joint work with Jonah Swann and, separately, with Kyle Hayden.
Gage Martin, Boston College
Jonathan Zung, Princeton University
Valeriano Aiello, Universität Bern, Mathematisches Institut
Cameron Rudd, University of Illinois Urbana-Champaign
Other relevant information.
Previous semesters:
Spring 2021, Fall 2020, Spring 2020, Fall 2019, Spring 2019, 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, 2010/11, Spring 2010, Fall 2009, Spring 2009, Fall 2008, Spring 2008, Fall 2007, Spring 2007, Fall 2006.Other area seminars.
- Columbia Symplectic Geometry/Gauge Theory Seminar
- All Columbia Math Dept Seminars
- CUNY Geometry and Topology Seminar
- CUNY Complex Analysis & Dynamics Seminar
- CUNY Magnus Seminar
- Princeton Topology Seminar.