Please note that the list below only shows forthcoming events, which may not include regular events that have not yet been entered for the forthcoming term. Please see the past events page for a list of all seminar series that the department has on offer.

 

Past events in this series


Tue, 17 Nov 2026
14:00
L6

Codimension-4 singularities in nilpotent orbit closures and symmetric pairs

Mengwei Hu
(John Hopkins University)
Abstract
In type A, nilpotent orbits are parametrized by partitions, and the singularities of their closures can be studied using transverse Slodowy slices. The classical work of Kraft and Procesi describes the minimal singularities of nilpotent orbit closures through simultaneous row and column removals.
 
In this talk, we study codimension-4 singularities in nilpotent orbit closures, where intermediate orbits may occur, using Maffei's realization of nilpotent Slodowy slices as Nakajima quiver varieties. We also construct quiver-variety involutions realizing Lie algebra anti-involutions and describe their fixed-point loci as singular Lagrangian subvarieties. These Lagrangians are closely related to the geometric classification of Harish-Chandra modules over quantizations of nilpotent orbits.
Tue, 24 Nov 2026
14:00
L6

The Geometry of Intertwining Operators

Johannes Carl Droschl
(Aarhus University)
Abstract

Given a p-adic group G, one would like to find a systematic way of constructing all its irreducible representations. As a first approximation, one can parabolically induce irreducible representations of Levi subgroups of G, however, the resulting representations are often reducible. A more refined approach is to consider (analytic) intertwining operators between such induced representations, whose images turn out to be irreducible in many cases. These intertwining operators have proven to be highly useful in a variety of problems, yet their general behavior remains far from fully understood. In the case of general linear groups, conjectures relate their behavior to the geometry of the cotangent bundle of the space of Langlands parameters.

This talk offers a gentle introduction to these topics and reports on recent progress towards these conjectures.

Tue, 01 Dec 2026
14:00
L6

TBC

Mario Marcos Losada
(Mathematical Institute University of Oxford )
Abstract

to follow