Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: What determines the slope of the colour-magnitude relation of elliptical
  galaxies in the hierarchical clustering scenario?
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org