Skip to main content

All Questions

Filter by
Sorted by
Tagged with
0 votes
0 answers
144 views

Cartesian square in the category of Algebraic stacks

Suppose we have a commutative diagram of Artin stacks $ \newcommand{\ra}[1]{\kern-1.5ex\xrightarrow{\ \ #1\ \ }\phantom{}\kern-1.5ex} \newcommand{\ras}[1]{\kern-1.5ex\xrightarrow{\ \ \smash{#1}\ \ }\...
S.D.'s user avatar
  • 494
1 vote
0 answers
125 views

2-shifted 2-form on the classifying stack 𝐵𝐺

Let $G$ be a reductive group. A $2$-shifted $2$-form on the classifying stack $BG$ is by definition a a morphism of quasi-coherent complexes \begin{equation} \mathcal O_{BG}\rightarrow (\wedge^2 \...
S.D.'s user avatar
  • 494
1 vote
0 answers
309 views

Is there an intrinsic Gauss map?

$\DeclareMathOperator\GL{GL}\DeclareMathOperator\Gr{Gr}$This may all be well known, too vague, or stupid; my apologies. The Gauss map is defined by embedding your $k$-dimensional smooth scheme/...
Leo Herr's user avatar
  • 1,084
20 votes
7 answers
3k views

What are the occurrences of stacks outside algebraic geometry, differential geometry, and general topology?

What are the occurrences of the notion of a stack outside algebraic geometry, differential geometry, and general topology? In most of the references, the introduction of the notion of a stack takes ...
Praphulla Koushik's user avatar
4 votes
0 answers
278 views

connection on principal bundles over algebraic/geometric stacks

Is there a notion of connection on a principal bundle over an algebraic or geometric stack? By a geometric stack, I mean a stack over category of manifolds that is representable by a Lie groupoid; ...
Praphulla Koushik's user avatar
5 votes
1 answer
366 views

K-theory for a (geometric) stack

There is a notion of $K$-theory for a manifold $M$. Is there a notion of $K$-theory for a stack $\mathcal{D}\rightarrow \text{Man}$ that is representable by a Lie groupoid $\mathcal{G}$; that is $...
Praphulla Koushik's user avatar
2 votes
0 answers
348 views

Notions of algebraic/differential geometry of scheme/manifolds extended to algebraic/differential stacks

Given a manifold, one can associate a stack over the category of manifolds, which is a differential geometric stack. This gives a functor $\text{Man}\rightarrow \text{D.Stacks}$. This is an embedding....
Praphulla Koushik's user avatar