Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The very rich massive post-main-sequence star population of the open
  cluster Westerlund 1
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol