Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: How to optimally parametrize deviations from General Relativity in the
  evolution of cosmological perturbations
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
18
The categories of this paper are: econ
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math