Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Amorphous carbon a promising material for sodium ion battery anodes: a
  first principles study
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat