Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A Riccati differential equation and free subgroup numbers for lifts of
  $\PSL_2(\Z)$ modulo powers of primes
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th