Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: 'Senator, We Sell Ads': Analysis of the 2016 Russian Facebook Ads
  Campaign
2
The categories of this paper are: math
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom