Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black holes and class groups   The theory of quadratic forms and class numbers has connections to many
classical problems in number theory. Recently, class numbers have appeared in
the study of black holes in string theory. We describe this connection and
raise questions in the hope of inspiring new collaborations between number
theorists and physicists.

33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics