Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Critical Star-Formation Rates for Reionization: Full Reionization occurs
  at z = 7
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph