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6 votes
0 answers
245 views

A group action on another group action quotient: how to best describe the resulting structure and does it have a name?

Suppose I have an action $\alpha:G\times X\to X$ of a group $G$ on a set $X$ and, on top of that, an action $\beta:H\times(X/G)\to(X/G)$ of another group $H$ on the set of $G$-orbits. Is there a nice ...
მამუკა ჯიბლაძე's user avatar
6 votes
0 answers
237 views

Fundamental class in equivariant K-theory

I'm looking for an accessible reference for the definition of the fundamental class in equivariant K-theory. The setup I'm interested in is the following: suppose $V$ is a vector space equipped with ...
clementine's user avatar
5 votes
0 answers
77 views

Equivariant corner straightening

Equivariant corner straightening is usually mentioned in the literature without further explanation. What would be a reference where this is done (more or less) carefully for compact Lie group actions ...
Igor Belegradek's user avatar
4 votes
0 answers
135 views

Pushforward of invariant measures (equivariant Moser theorem)

There is a well-known theorem that between any two absolutely continuous Borel probability measures $\mu$ and $\nu$ on $\mathbb{R}^n$ there is an increasing triangular transformation $T : \mathbb{R}^n ...
ivan's user avatar
  • 41
4 votes
0 answers
243 views

Equivariant sheaves basics reference

I am looking for a reference for basic facts about actions of linear algebraic groups and their Lie-algebras on $\mathcal O_X$-modules. For example I could not find a reference the following: Let $...
Jan Weidner's user avatar
  • 13.2k
3 votes
0 answers
69 views

Equivariant smooth approximation

Suppose we have a compact manifold $M$ with the action of a compact group $G$. Consider the space of $C^l$ $G$-equivariant diffeomorphisms $\text{Diff}_G^{l}(M)$ with the $C^l$ topology and the space ...
cr1t1cal's user avatar
  • 755
3 votes
0 answers
662 views

Equivariant Riemann-Roch on DM stacks?

Does an equivariant version of (Toen)-Riemann-Roch theorem hold say over a smooth Deligne-Mumford stack $X$ over the complex numbers? Any references that state this explicitely? Are there formulas ...
Qfwfq's user avatar
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1 vote
0 answers
182 views

G-Modules on X=G/H modules on X/H ?

I think it is true that $G$-equivariant sheaves on $X$ are equal to $G/H$ equivariant sheaves on $X/H$. More precisely I'm interested in the following statement: Given an algebraic group $G$ with ...
Jan Weidner's user avatar
  • 13.2k