Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The separation problem for regular languages by piecewise testable
  languages
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph