Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On Darboux transformations for the derivative nonlinear Schr\"odinger
  equation
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat