Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Understanding the temporal evolution of COVID-19 research through
  machine learning and natural language processing
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex