Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A Gravitational Wave Background from Primordial Black Hole Lattices in
  Matter Dominated Era
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas