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11 votes
0 answers
451 views

Semistability of tensor products under automorphisms of tensored vector spaces

Let $A,B,C,D,E,F$ be vector spaces over a field. Let $x\in A \otimes B \otimes C$ and $y \in D \otimes E \otimes F$ be tensors that are semistable with respect to the natural actions of $\text{SL}(A) ...
Will Sawin's user avatar
  • 149k
10 votes
0 answers
238 views

Progress since Luna's theorem on smooth invariants

In 1976, Luna proved the following important theorem of smooth invariant theory: Let $G$ be a real reductive Lie group and a representation of $G$ on a real finite dimensional vector space $V$. ...
Igor Khavkine's user avatar
5 votes
0 answers
351 views

What representation theoretic properties does the semi-invariant ring tell us?

I'm asking this question as a continuation of discussion and answer given by Hugh Thomas at the following post: Why do people study semi-invariant ring (in general)? I have been studying about semi-...
It'sMe's user avatar
  • 839
5 votes
0 answers
146 views

Injectivity of a standard map in quiver representation

Let $X$ be a smooth projective variety, and assume its divisor class group is finite and free. Let $E_1,E_2,\ldots,E_n$ be line bundles on $X$. Define $L_k=E_1+\ldots E_k$, and let $Q$ be the ...
Xuqiang QIN's user avatar
4 votes
0 answers
140 views

Scaling-Invariant Orbits of Semisimple Group Representations

Let $G$ be a connected, simply-connected complex semisimple linear algebraic group, and let $V$ be a finite-dimensional complex $G$-module. Note that if $V$ is the adjoint representation of $G$, then ...
Peter Crooks's user avatar
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3 votes
0 answers
126 views

Parametrization of indecomposable modules via quiver varieties

Let $k$ be an algebraically closed field, $Q$ a quiver without oriented cycles and $m^\alpha (Q)$ the variety of quiver representations with dimension vector $\alpha$. There is a canonical algebraic ...
kevkev1695's user avatar
3 votes
0 answers
235 views

Moduli space of nilpotent Lie algebras

Fix a nilpotent Lie algebra $L$ over some char 0 field $k$ which is naturally graded, i. e. isomorphic to graded algebra $\bar L$ associated to lower central filtration. I'm interested in some ...
Denis T's user avatar
  • 4,600
1 vote
0 answers
144 views

Non-empty stable locus of an irreducible component

I have a vague question: Let $X$ be an algebraic pre-scheme and $G$ be a linear reductive group. Consider the G.I.T. quotient $X{/\!/}G$. Is there any result (maybe in some special case) which tells ...
It'sMe's user avatar
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