Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Effect of Twisted Magnetic Field on the Period Ratio P_1/P_2 of
  Nonaxisymmetric MHD Waves
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th