Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The behavior of the pitch angle of spiral arms depending on optical
  wavelength
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom