Department of Mathematics Calendar

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Abstracts

Week of September 20, 2026

September 21, 2026
Algebraic and Arithmetic Geometry Seminar	Complex structures on S^6	4:30pm - KT 801	A recent manuscript written by Claude under the direction of Levent Alpoge constructs a 1-parameter family of compact complex threefolds diffeomorphic to S^6. I will describe the main geometric ideas behind the construction and outline the proof. If time permits, I will remark on possible future research directions.
Arithmetic Algebraic Geometry	Complex structures on S^6	4:30pm - KT 801	A recent manuscript written by Claude under the direction of Levent Alpoge constructs a 1-parameter family of compact complex threefolds diffeomorphic to S^6. I will describe the main geometric ideas behind the construction and outline the proof. If time permits, I will remark on possible future research directions.

September 22, 2026
Geometric Analysis Learning Seminar	Pre-Talk	4:00pm - KT 801	This pre-talk will provide background for the Geometric Analysis and Application Seminar on 09/22.
Geometric Representation Theory Seminar	Quantum Harish-Chandra bimodules at roots of unity and affine Hecke category	4:30pm - KT 221	Abstract: Classical Harish-Chandra bimodules are related to many objects in representation theory such as infinite dimensional representations of complex groups viewed as real groups, category O and character sheaves. The notion of Harish-Chandra bimodules for quantum groups was introduced in the works about topological quantum field theory of surfaces. I will mention some results about quantum Harish-Chandra bimodules at odd order roots of unity, connect them to affine Soergel bimodules and coherent sheaves on Steinberg variety. Seminar website: https://sites.google.com/view/yale-grt-seminar/home

September 24, 2026
Analysis	Stability of small BGK waves	4:00pm - KT 201	Bernstein–Greene–Kruskal (BGK) waves are fundamental inhomogeneous steady states of the one-dimensional Vlasov–Poisson system, introduced in 1957. Despite their classical role, their stability theory remains largely open. The only known result is by Guo-Lin, who considered a special class of small BGK waves. In this talk, I will present a stability–instability criterion for small BGK waves bifurcating from homogeneous equilibria, determined by the behavior of the particle distribution near the separatrix. This is joint work with D. Bian, E. Grenier and B. Pausader.

September 25, 2026
Friday Morning Seminar	Friday morning seminar	10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00pm - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801 , 10:00am to 11:00am - Kline Tower 801
Learning seminar on Groups, Geometry and Dynamics	Discrete groups acting ergodically on the boundary.	2:00pm to 3:15pm - KT 801	I will talk about the existence of bounded harmonic functions on hyperbolic manifolds and more generally locally symmetric spaces, explains how it relates to the fundamental group acting ergodically on the Furstenberg boundary, and discuss some new and old results about this topic . Based on joint work with Subhadip Dey and Mikolaj Fraczyk.