Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Finiteness of Fixed Equilibrium Configurations of Point Vortices in the
  Plane with Background Flow
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph