Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A non-degenerate scattering theory for the wave equation on extremal
  Reissner-Nordstrom
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat