Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: BPS states and supersymmetric index in N=2 type I string vacua
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat