Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Mg II h + k emission lines as stellar activity indicators of main
  sequence F-K stars
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs