Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scattering solutions of Bethe-Salpeter equation in Minkowski and
  Euclidean spaces   We shortly review different methods to obtain the scattering solutions of the
Bethe-Salpeter equation in Minkowski space. We emphasize the possibility to
obtain the zero energy observables in terms of the Euclidean scattering
amplitude.

9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio