Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The scaling relations of early--type galaxies in clusters I. Surface
  photometry in seven nearby clusters
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph