Skip to main content

All Questions

Filter by
Sorted by
Tagged with
1 vote
0 answers
133 views

What is Pic of the torus global affine Grassmannian?

Let $T$ be a torus and $X$ a proper smooth curve over characteristic $0$ algebraically closed field $k$. What is $\text{Pic}(\text{Gr}_{T,X^n})$? Here $\text{Gr}_{T,X^n}$ is the BD Grassmannian over $...
4 votes
0 answers
260 views

Stratified fibration property of the "Ran" affine Grassmannian

Let us consider the so-called Ran Grassmannian $Gr_{Ran}$, i.e. the geometric object defined e.g. in [Zhu, An Introduction to the affine Grassmannian and the Geometric Satake equivalence, Definition 3....
5 votes
1 answer
445 views

Drinfeld Sokolov and the semiinfinite flag variety

For a long time I've been confused about Drinfeld Sokolov/BRST reduction/semiinfinite cohomology for affine Lie algebras. Most treatments define it in what to me feels like a fairly ad-hoc way, by ...
8 votes
1 answer
599 views

Affine vs Yokonuma

Let $G=GL_n$. Let us start with the Hecke algebra $H_n$. It acts on K(constructible sheaves on $G/B$) by Hecke correpondences and on K(coherent sheaves on $G/B$) by Lusztig's construction [1]. Now we ...
5 votes
1 answer
605 views

Are Strata of the affine Grassmannian total spaces of equivariant vector bundles over flag varieties

This question is closely related to Peter Crooks question. Strata of the Affine Grassmannian Let $G$ be a complex reductive group, $\mathcal{K}:= \mathbb{C}((t))$, $\mathcal{O}:= \mathbb{C}[[t]]$ and ...