Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quiver algebras, weighted projective lines, and the Deligne-Simpson
  problem   We describe recent work on preprojective algebras and moduli spaces of their
representations. We give an analogue of Kac's Theorem, characterizing the
dimension types of indecomposable coherent sheaves over weighted projective
lines in terms of loop algebras of Kac-Moody Lie algebras, and explain how it
is proved using Hall algebras. We discuss applications to the problem of
describing the possible conjugacy classes of sums and products of matrices in
known conjugacy classes.

18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg