Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the class of languages recognizable by 1-way quantum finite automata   It is an open problem to characterize the class of languages recognized by
quantum finite automata (QFA). We examine some necessary and some sufficient
conditions for a (regular) language to be recognizable by a QFA. For a subclass
of regular languages we get a condition which is necessary and sufficient.
  Also, we prove that the class of languages recognizable by a QFA is not
closed under union or any other binary Boolean operation where both arguments
are significant.

30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
9
The categories of this paper are: nlin
1
The categories of this paper are: cs