Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A semi-analytic model of pairwise velocity distribution between dark
  matter halos
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ