Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Damped Lyman-alpha Absorbers in Cosmological SPH Simulations: the
  "metallicity problem"
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
29
The categories of this paper are: funct-an