Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Cosmological perturbations for imperfect fluids
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th