Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On complexity of regular realizability problems   A regular realizability (RR) problem is testing nonemptiness of intersection
of some fixed language (filter) with given regular language. We study here
complexity of RR problems. It appears that for any language L there exists RR
problem equivalent to L under disjunctive reductions on nondeterministic log
space. It implies that for any level of polynomial hierarchy there exists
complete RR problem under polynomial reductions.

18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math