Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Quantum Hall effect at half-filled Landau level: Pairing of composite
  fermions
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex