Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Matroids and Geometric Invariant Theory of torus actions on flag spaces   We apply a theorem of Gel'fand, Goresky, MacPherson, and Serganova about
matroid polytopes to study semistability of partial flags relative to a
T-linearized ample line bundle of a flag space F = SL(n)/P where T is a maximal
torus in SL(n) and P is a parabolic subgroup containing T. We find that the
semistable points are all detected by invariant sections of degree one
regardless of the line bundle or linearization thereof, provided there exists
at least one nonzero invariant section of degree one. In this case the degree
one sections are sufficient to give a well defined map from the G.I.T. quotient
F//T to projective space.
  Additionally, we show that the closure of any T-orbit in SL(n)/P is a
projectively normal toric variety for any projective embedding of SL(n)/P.

22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th