Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The number density and mass density of star-forming and quiescent
  galaxies at 0.4 < z < 2.2
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org