Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quiver Grassmannians and degenerate flag varieties   Quiver Grassmannians are varieties parametrizing subrepresentations of a
quiver representation. It is observed that certain quiver Grassmannians for
type A quivers are isomorphic to the degenerate flag varieties investigated
earlier by the second named author. This leads to the consideration of a class
of Grassmannians of subrepresentations of the direct sum of a projective and an
injective representation of a Dynkin quiver. It is proven that these are
(typically singular) irreducible normal local complete intersection varieties,
which admit a group action with finitely many orbits, and a cellular
decomposition. For type A quivers explicit formulas for the Euler
characteristic (the median Genocchi numbers) and the Poincare polynomials are
derived.

12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol