Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Multifrequency analysis of 21 cm fluctuations from the Era of
  Reionization
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th