Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Electron density distribution and screening in rippled graphene sheets
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat