Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Semi-invariants of mixed representations of quivers   The notion of mixed representations of quivers can be derived from ordinary
quiver representations by considering the dual action of groups on "vertex"
vector spaces together with the usual action. A generating system for the
algebra of semi-invariants of mixed representations of a quiver is determined.
This is done by reducing the problem to the case of bipartite quivers of the
special form and by introducing a function DP on three matrices, which is a
mixture of the determinant and two pfaffians.

23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ