Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Robust optical conductivity in gapped graphene
3
The categories of this paper are: physics
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci