Informal Geometry and Topology Seminar
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Posted November 28, 2007

Last modified July 25, 2018

Framed knot contact homology

Informal Geometry and Topology Seminar
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Posted December 3, 2007

Last modified July 25, 2018

Reading Seminar

Informal Geometry and Topology Seminar
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Posted May 6, 2008

Last modified July 25, 2018

Reading Seminar

Informal Geometry and Topology Seminar
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Posted January 11, 2017

10:00 am Lockett 233Organizational meeting

Informal Geometry and Topology Seminar
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Posted January 17, 2017

10:30 am - 12:00 pm Lockett 233
Shea Vela-Vick, Louisiana State University

A brief introduction to Heegaard Floer invariants

In this talk, we introduce some of the basic definitions and tools used in Heegaard Floer theory, with an emphasis on applications to knot theory.

Informal Geometry and Topology Seminar
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Posted January 25, 2017

10:30 am - 12:00 pm Lockett 233
Kyle Istvan, Louisiana State University

Invariants of Singular Knots

Informal Geometry and Topology Seminar
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Posted February 3, 2017

10:30 am - 12:30 pm Lockett 233
Ryan Leigon, Louisiana State University

First Examples in Bordered Floer Homology

Informal Geometry and Topology Seminar
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Posted February 3, 2017

10:30 am - 12:30 pm Lockett 233
Jose Ceniceros, Louisiana State University

Open Books and Contact Geometry

Informal Geometry and Topology Seminar
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Posted February 3, 2017

10:30 am - 12:30 pm Lockett 233
Federico Salmoiraghi, Department of Mathematics, LSU

TBD

Informal Geometry and Topology Seminar
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Posted February 3, 2017

10:30 am - 12:30 pm Lockett 233
Andrew Holmes, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted August 23, 2017

Last modified August 29, 2017

Federico Salmoiraghi, Department of Mathematics, LSU

An introduction to Heegaard Floer homology

Abstract: In 2001 Ozsvath and Szabo introduced Heegaard Floer homology, an invariant of three manifolds that can be calculated from a particular class of Heegaard diagram for the manifold. In this talk, after a brief outline of the construction of the invariant, I will introduce some of the different versions of Heegaard Floer homology and compute some example.

Informal Geometry and Topology Seminar
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Posted August 23, 2017

Last modified September 12, 2017

Ryan Leigon, Louisiana State University

Bordered Heegaard Floer Homology

Abstract: Heegaard Floer theory yields powerful invariants of 3-manifolds, but it is often difficult to compute. Bordered Floer allows us to do computations by cutting a 3-manifold into simple pieces, where computations are easy, and then pasting the pieces back together. I will provide a brief introduction to the theory before giving an accessible yet non-trivial example.

Informal Geometry and Topology Seminar
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Posted September 20, 2017

10:30 am - 12:00 pm Lockett 233

Ryan Leigon, Louisiana State University

Federico Salmoiraghi, Department of Mathematics, LSU

Equivalence of gluing maps in Heegaard Floer theory

Abstract: We show that the gluing mas in Heegaard Floer theory defined by Honda, Kazez and Matic and by Zarev are equivalent.

Informal Geometry and Topology Seminar
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Posted August 23, 2017

Last modified September 11, 2017

Yu-Chan Chang, Louisiana State University

Introduction to bounded cohomology of discrete groups

Abstract: In this introductory talk, we will focus on bounded cohomology of discrete groups with real or integer coefficient. I will talk about the bounded cohomology of Gromov hyperbolic groups and amenable groups. Also, we will discuss the comparison map, which is the map from the bounded cohomology to the usual cohomology.

Informal Geometry and Topology Seminar
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Posted October 3, 2017

10:20 am - 11:20 am Lockett 233
Yu-Chan Chang, Louisiana State University

Introduction to bounded cohomology of discrete groups II

Abstract: We continue our discussion from last week. In this talk, I will describe the construction of non-trivial quasimorphisms on free groups. This shows that free groups have non-trivial second bounded cohomology groups while the usual cohomology groups are trivial. We will also discuss the quasi-morphism on abelian groups. If time permits, I will talk about Gromov hyperbolic groups.

Informal Geometry and Topology Seminar
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Posted August 23, 2017

Last modified October 3, 2017

Kent Vashaw, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted October 6, 2017

Last modified October 16, 2017

Robin Koytcheff, University of Louisiana, Lafayette

Finite-type invariants of knots, links, and string links

Abstract: Finite-type knot invariants (a.k.a. Vassiliev invariants) are an important class of invariants in that they conjecturally approximate all knot invariants and hence separate knots. They may also be defined for (closed) links and string links, and they are known to separate string links up to link homotopy. In other words, they are a complete invariant of string links where each component may pass through itself. This parallels (and is related to) a story about the kappa invariant, which conjecturally separates closed links up to link homotopy. In joint work with F. Cohen, Komendarczyk, and Shonkwiler, we showed that the kappa invariant separates string links up to link homotopy. In this talk, we will focus on the elementary, purely combinatorial description of finite-type invariants.

Informal Geometry and Topology Seminar
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Posted October 24, 2017

10:30 am - 12:00 pm Lockett 233
Kent Vashaw, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted August 23, 2017

Last modified October 24, 2017

Rima Chatterjee, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted November 7, 2017

10:30 am - 12:00 pm Lockett 233
Nurdin Takenov, Louisiana State University

Vassiliev Invariants

Informal Geometry and Topology Seminar
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Posted August 25, 2017

Last modified November 15, 2017

Sudipta Ghosh, Louisiana State University

Seiberg-Witten invariants of 4-manifolds with free circle actions

Informal Geometry and Topology Seminar
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Posted August 23, 2017

Last modified January 23, 2018

Rob Quarles, Louisiana State University

The Alexander module

Informal Geometry and Topology Seminar
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Posted January 24, 2018

Last modified January 30, 2018

Rima Chatterjee, Louisiana State University

Transverse universal links

Informal Geometry and Topology Seminar
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Posted January 24, 2018

10:00 am - 12:00 pm Lockett 233
Ryan Leigon, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted February 20, 2018

10:30 am - 12:00 pm Lockett 233Configuration Spaces and Graph Realizability

Abstract: Embed a graph G generically into R^n as a bar framework (edges are rigid straight bars which are free to rotate around vertices). Fixing the edge lengths given by the embedding, what is the smallest integer d such that G can embed into R^d with the same edge lengths? As an example, no n-simplex can be generically embedded into R^{n-1}. Viewing the n-simplex as a complete graph, we see that the non-realizability of the n-simplex is a property of the complete graph. Are simplicies the minimal objects in some sense with regards to realizability? No, we can find generic 4-dim embeddings of the octahedron which do not admit 3-dim realizations. We will demonstrate a proof of this fact and examine several different characterizations of this correspondence between graphs and certain simplicial complexes as we try to build towards more complex and higher dimensional objects. This is a work in progress.

Informal Geometry and Topology Seminar
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Posted January 24, 2018

Last modified February 27, 2018

Yu-Chan Chang, Louisiana State University

Simplicial Volume

Abstract: Gromov introduced the simplicial volume in 1982, it is an invariant of manifolds. While several vanishing and non-vanishing results for the simplicial volume are known by now, the exact value of non-vanishing simplicial volumes is difficult to compute. In this talk, the bounded cohomology of spaces will be defined, then we will discuss some basic properties of simplicial volume and some celebrated results by Gromov and Thurston.

Informal Geometry and Topology Seminar
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Posted January 24, 2018

Last modified February 27, 2018

Federico Salmoiraghi, Department of Mathematics, LSU

TBD

Informal Geometry and Topology Seminar
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Posted January 24, 2018

10:00 am - 12:00 pm Lockett 233
Sudipta Ghosh, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted March 19, 2018

10:30 am - 12:00 pm Lockett 233
Kent Vashaw, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted January 24, 2018

Last modified March 19, 2018

Nurdin Takenov, Louisiana State University

TBD

Informal Geometry and Topology Seminar
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Posted August 27, 2018

1:30 pm - 3:00 pm Lockett 233
Ignat Soroko, Louisiana State University

Right-angled Artin groups and their subgroups

I will define right-angled Artin groups, consider few examples and talk about some interesting classes of their subgroups: special subgroups in the sense of Haglund and Wise, and Bestvina-Brady kernels.

Informal Geometry and Topology Seminar
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Posted August 16, 2018

Last modified September 7, 2018

Andrew Zimmer, Louisiana State University

Metrics in several complex variables

Abstract: In this talk I'll define three classical metrics in several complex variables: the Kobayashi metric, the Bergman metric, and the K{"a}hler-Einstein metric. After introducing these metrics, I'll describe how their geometric properties can be used to solve problems. The talk won't assume any prior background in complex analysis.

Informal Geometry and Topology Seminar
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Posted August 27, 2018

Last modified September 7, 2018

Ryan Leigon, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

1:30 pm - 3:00 pm Lockett 233
Ryan Leigon, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

Last modified September 24, 2018

Yilong Wang, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

Last modified September 17, 2018

Kent Vashaw, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

1:30 pm - 3:00 pm Lockett 233
Lucas Meyers, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

1:30 pm - 3:00 pm Lockett 233
Sudipta Ghosh, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

1:30 pm - 3:00 pm Lockett 233
Rima Chatterjee, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted November 8, 2018

1:30 pm - 3:00 pm
Rima Chatterjee, Louisiana State University

Branches covers of contact manifolds II

Informal Geometry and Topology Seminar
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Posted August 27, 2018

Last modified November 8, 2018

Rob Quarles, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

1:30 pm - 3:00 pm Lockett 233
Natthawut Phanachet, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted August 27, 2018

Last modified November 8, 2018

Nurdin Takenov, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 16, 2019

1:30 pm - 3:00 pm Lockett 233
Shea Vela-Vick, Louisiana State University

Arnold's dream: in search for higher-order helicity invariants

Abstract: Arnold dreamed of a hierarchy of helicity invariants which could provide lower bounds for the L_2-energy of a vector field under appropriate deformations. Ordinary helicity is a field analogue of the standard linking number between curves, and this correspondence quickly leads to an integral expression for helicity. The general expectation is that higher-order helicity invariants should be obtained as field generalizations of higher order linking invariants, of which Milnor''s triple-linking number is the first in line. In this talk, I''ll survey some of the history behind helicity invariant and show how one can use configuration space techniques to obtain a geometrically natural integral expression for the Milnor triple-linking number.

Informal Geometry and Topology Seminar
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Posted January 22, 2019

1:30 pm - 3:00 pm Lockett 233
Mike Wong, Louisiana State University

GRID invariants obstruct decomposable Lagrangian cobordisms

Abstract: Ozsvath, Szabo, and Thurston defined several combinatorial invariants of Legendrian links in the 3-sphere using grid homology, which is a combinatorial version of knot Floer homology. These, collectively called the GRID invariants, are known to be effective in distinguishing some Legendrian knots that have the same classical invariants. In this talk, we describe a recent result that the GRID invariants provide an obstruction to the existence of decomposable Lagrangian cobordisms between Legendrian links. This obstruction is stronger than the obstructions from the Thurston-Bennequin and rotation numbers, and is closely related to a recent result by Golla and Juhasz. This is joint work with John Baldwin and Tye Lidman.

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Scott Baldridge, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

Last modified February 5, 2019

Anton Zeitlin, LSU

Hidden Homotopy Symmetries of Einstein Field Equations

Abstract: We demonstrate that the Einstein field equations with extra fields known as B-field and dilaton, have a nontrivial underlying algebraic structure, known as homotopy Gerstenhaber algebra. Such homotopy algebra is a natural object associated to Courant algebroid in the vertex algebra formalism. We show that the Einstein equations coincide with the Maurer-Cartan equations for the L-infinity part of such Gerstenhaber algebra.

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Andrew Zimmer, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Ryan Leigon, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

Last modified February 21, 2019

Yu-Chan Chang, Louisiana State University

Introduction to handlebody groups

Abstract: Handlebody group is the mapping class group of a 3-dimensional handlebody, it is a subgroup of the mapping class group of the boundary surface of that handlebody. In this introductory talk, I will talk about some properties of handlebody groups and how different they are from the surface mapping groups.

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Federico Salmoiraghi, Department of Mathematics, LSU

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Nurdin Takenov, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 1:30 pm Lockett 233
Rima Chatterjee, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Lucas Meyers, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Sean Bibby, Louisiana State University

TBA

Informal Geometry and Topology Seminar
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Posted January 27, 2019

1:30 pm - 3:00 pm Lockett 233
Natthawut Phanachet, Louisiana State University

TBA