Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Efficient Photometric Selection of Quasars from the Sloan Digital Sky
  Survey: II. ~1,000,000 Quasars from Data Release Six
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin