[Topology.beta] AG Tuesday

[Rot, T.O. (Thomas)]

Showtime in 5!

From: "Topology.beta" <topology.beta-bounces at listserver.vu.nl> on behalf of "Rot, T.O. (Thomas)" <t.o.rot at vu.nl>
Date: Monday, 11 March 2024 at 23:37
To: "_list_topology.beta" <topology.beta at listserver.vu.nl>, "Fusco, D. (Deborah)" <d.fusco at student.vu.nl>
Subject: [Topology.beta] AG Tuesday

Dear all,

Lots of events this week!

Tuesday, which is either tomorrow or today depending when you read your email, we have a guest in the AG from Bonn.

AG: 12-03-2024: 11:00 in Maryam: Karandeep Singh (Bonn) : Stability problems and differential graded Lie algebras

Abstract: Stability problems appear in various forms throughout geometry and algebra. For example, given a vector field $X$ on a manifold that vanishes in a point, when do all nearby vector fields also vanish somewhere? As an example in algebra, we can consider the following question: Given a Lie algebra $\mathfrak g$, and a Lie subalgebra $\mathfrak h$, when do all deformations of the Lie algebra structure on $\mathfrak g$ admit a Lie subalgebra close to $\mathfrak h$? I will show that both questions are instances of a general question about differential graded Lie algebras, and under a finite-dimensionality condition which is satisfied in the situations above, I will give a sufficient condition for a positive answer to the general question. I will then discuss the application to fixed points of Lie algebra actions.

This Friday we have a DDT&G with a guest from Columbia university (New York)

15-03-2024 14:00-16:30 Amsterdam NU building 9-A46: Francesco Lin <https://www.math.columbia.edu/~flin/> (Columbia): Topology of the Dirac equation on spectrally large three-manifolds
Abstract: In the first talk, I will review the classical work of Atiyah and Singer describing the homotopy type of the family of Dirac operators on a spin Riemannian manifold, and its consequences regarding metrics of positive scalar curvature. In the second talk, I will discuss how one can exploit the Seiberg-Witten equations and Floer theory to obtain more detailed information about the structure of the family in the case of a three-manifold for which the spectral gap of the Hodge Laplacian on coexact 1-forms is large compared to the curvature. For concreteness, we will have a special focus on the case of the n-torus throughout the talks.

I hope to see you both. As always, your students are also very welcome to attend!

Best,
Thomas

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://listserver.vu.nl/pipermail/topology.beta/attachments/20240312/b7db3b07/attachment-0001.html>