Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The influence of galaxy mergers on the mass dispersion of brightest
  cluster galaxies
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom