Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Cauchy problem for a semilinear ordinary differential equation in
  the homogeneous and isotropic spacetime
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph