Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New periodic solutions for three or four identical vortices on a plane
  and a sphere   In this paper we describe new classes of periodic solutions for point
vortices on a plane and a sphere. They correspond to similar solutions
(so-called choreographies) in celestial mechanics.

32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph