Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Amplitude equations for weakly nonlinear two-scale perturbations of free
  hydromagnetic convective regimes in a rotating layer
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat