Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A decoupled system of hyperbolic equations for linearized cosmological
  perturbations
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an