Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Invariant Tori of a Two Dimensional Periodic System with the
  Linear-Cubic Unperturbed Part
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol