Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Van der Waals heteroepitaxy of air stable quasi-free standing silicene
  layers on CVD epitaxial graphene/6H-SiC
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc