Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Pulsar Timing Array Constraints on Primordial Black Holes with NANOGrav
  11-Year Data Set
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org