Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Subgroups of $SL_2(\mathbb{Z})$ characterized by certain continued
  fraction representations
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys