Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Long range scattering for the complex-valued Klein-Gordon equation with
  quadratic nonlinearity in two dimensions
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat