Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Sound and Heat Absorption by a 2D Electron Gas in an Odd-Integer
  Quantized-Hall Regime
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom