Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Complete classification of purely magnetic, non-rotating and
  non-accelerating perfect fluids
1
The categories of this paper are: cs
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol