Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Electron-Phonon Spectral Density of MgB2 from Optical Data, through
  Maximum Entropy
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex