Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: First principle electronic, structural, elastic, and optical properties
  of strontium titanate
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol