Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On structure of solutions of 1-dimensional 2-body problem in
  Wheeler-Feynman electrodynamics
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
2
The categories of this paper are: math
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg