Le contenu de cette page n’est pas disponible en français. Veuillez nous en excuser.

# Vidéotheque

Since 2002 Perimeter Institute has been recording seminars, conference talks, public outreach events such as talks from top scientists using video cameras installed in our lecture theatres.  Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities.

Recordings of events in these areas are all available and On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA)PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.

Accessibly by anyone with internet, Perimeter aims to share the power and wonder of science with this free library.

## K-Motives and Koszul Duality

Vendredi juin 26, 2020
Speaker(s):

Koszul duality, as conceived by Beilinson-Ginzburg-Soergel, describes a remarkable symmetry in the representation theory of Langlands dual reductive groups. Geometrically, Koszul duality can be stated as an equivalence of categories of mixed (motivic) sheaves on flag varieties. In this talk, I will argue that there should be an an 'ungraded' version of Koszul duality between monodromic constructible sheaves and equivariant K-motives on flag varieties. For this, I will explain what K-motives are and present preliminary results.

Scientific Areas:

## A categorification of the Lusztig—Vogan module

Jeudi juin 25, 2020
Speaker(s):

Admissible representations of real reductive Lie groups are a key player in the world of unitary representation theory. The characters of irreducible admissible representations were described by Lustig—Vogan in the 80’s in terms of a geometrically-defined module over the associated Hecke algebra. In this talk, I’ll describe a categorification of this module using Soergel bimodules, with a focus on examples. This is work in progress.

Scientific Areas:

## An extension of Suzuki's functor to the critical level

Jeudi juin 25, 2020
Speaker(s):

Suzuki's functor relates the representation theory of the affine Lie algebra to the representation theory of the rational Cherednik algebra in type A. In this talk, we discuss an extension of this functor to the critical level, t=0 case. This case is special because the respective categories of representations have large centres. Our main result describes the relationship between these centres, and provides a partial geometric interpretation in terms of Calogero-Moser spaces and opers.

Scientific Areas:

## Parabolic Hilbert schemes via the Dunkl-Opdam subalgebra

Jeudi juin 25, 2020
Speaker(s):

In this note we give an alternative presentation of the rational
Cherednik algebra H_c corresponding to the permutation representation of
S_n. As an application, we give an explicit combinatorial basis for all
standard and simple modules if the denominator of c is at least n, and
describe the action of H_c in this basis. We also give a basis for the
irreducible quotient of the polynomial representation and compare it to
the basis of fixed points in the homology of the parabolic Hilbert

Scientific Areas:

## The physics of compact objects in general relativity.

Jeudi juin 25, 2020

The study of compact objects in the strong field regime needs a thorough understanding of the initial value problem in general relativity at the resence of hydrodynamical or magnetohydrodynamical sources. This is a twofold problem that includes general relativistic solutions that represent realistic astrophysical systems at a given moment in time as well as their subsequent evolutions.

Collection/Series:
Scientific Areas:

## Parabolic restriction for Harish-Chandra bimodules and dynamical R-matrices

Jeudi juin 25, 2020
Speaker(s):

The category of Harish-Chandra bimodules is ubiquitous in representation theory. In this talk I will explain their relationship to the theory of dynamical R-matrices (going back to the works of Donin and Mudrov) and quantum moment maps. I will also relate the monoidal properties of the parabolic restriction functor for Harish-Chandra bimodules to the so-called standard dynamical R-matrix. This is a report on work in progress, joint with Artem Kalmykov.

Scientific Areas:

## Relative critical loci, quiver moduli, and new lagrangian subvarieties

Jeudi juin 25, 2020
Speaker(s):

The preprojective algebra of a quiver naturally appears when computing
the cotangent to the quiver moduli, via the moment map. When considering
the derived setting, it is replaced by its differential graded (dg)
variant, introduced by Ginzburg. This construction can be generalized
using potentials, so that one retrieves critical loci when considering
moduli of perfect modules.
Our idea is to consider some relative, or constrained critical loci,
deformations of the above, and study Calabi--Yau structures on the

Scientific Areas:

## Geometric class field theory and Cartier duality

Mercredi juin 24, 2020

I will explain a generalized Albanese property for smooth curves, which implies Deligne's geometric class field theory with arbitrary ramification. The proof essentially reduces to some well-known Cartier duality statements. This is joint work with Andreas Hayash.

Scientific Areas:

## The Springer" representation of the DAHA

Mercredi juin 24, 2020
Speaker(s):

The Springer resolution and resulting Springer sheaf are key players in geometric representation theory. While one can construct the Springer sheaf geometrically, Hotta and Kashiwara gave it a purely algebraic reincarnation in the language of equivariant $D(\mathfrak{g})$-modules. For $G = GL_N$, the endomorphism algebra of the Springer sheaf, or equivalently of the associated $D$-module, is isomorphic to $\mathbb{C}[\mathcal{S}_n]$ the group algebra of the symmetric group. In this talk, I'll discuss a quantum analogue of this.

Scientific Areas:

## Modular representations and perverse sheaves on affine flag varieties

Mercredi juin 24, 2020
Speaker(s):

I will give an overview of a joint project with Simon Riche and Laura Rider and another one with Dima Arinkin aimed at a modular version of the equivalence between two geometric realization of the affine Hecke algebra and derived Satake equivalence respectively. As a byproduct we obtain a proof of the Finkelberg-Mirkovic conjecture and a possible approach to understanding cohomology of higher Frobenius kernels with coefficients in a G-module.

Scientific Areas:

## Lectures On-Demand

Watch on Perimeter's