Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Role of the E2g phonon in the superconductivity of MgB2: a Raman
  scattering study
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess