Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ground State thermodynamic and response properties of electron gas in a
  strong magnetic and electric field: Exact analytical solutions for a
  conventional semiconductor and for Graphene
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph