Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Hamburger Sternwarte plate archives: Historic long-term variability
  study of active galaxies based on digitized photographic plates
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th