categorification seminar


schedule

fall 2025 schedule
when wednesdays from 12:30 to 14:00
where pk-5675, uqam

log

fall 2025

The topic for this fall's seminar is Graded quiver varieties.

meeting 1, september 24th

Graded quiver varieties, representations of quantum affine algebras, and product monomial crystals
Nakajima introduced quiver varieties in order to give a geometric construction of representations of semisimple Lie algebras. Later, using equivariant cohomology/K-theory, he and Varagnolo extended these actions to Yangians/quantum affine algebras. I will give an overview of these constructions and explain how we can extract the combinatorics of the product monomial crystal. Finally, I will discuss two possible projects that we can work on using these ideas. In future talks, we will go into more detail on these topics.

Joel Kamnitzer

meeting 2, october 8th

A naïve introduction to quiver varieties
We will build our way to the definition of (unframed) quiver varieties using (easy) examples and naïve questions. The talk should be accessible to all.

Théo Pinet

meeting 3, october 29th

Introduction to quiver varieties
I'm planning to introduce Nakajima quiver varieties and go through some examples -- starting with the Hilbert scheme of $\mathbb{C}^2$, and, time permitting, also the resolutions of Kleinian singularities.

Leonid Rybnikov

meeting 4, november 5th

Graded quiver varieties and the product monomial crystal (part 1)
We will introduce graded quiver varieties and explain the bijection between their connected components and the product monomial crystal.

Alexis Leroux-Lapierre

meeting 5, november 12th

Graded quiver varieties and the product monomial crystal (part 2)

Alexis Leroux-Lapierre

meeting 6, november 19th

Crystal structure on connected components of graded quiver varieties

Artem Kalmykov

meeting 7, november 26th

Yangian actions on equivariant cohomology of cotangent bundles of partial flag varieties.

Joel Kamnitzer

references