Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Similarities and Differences between Relativistic Electron-Photon
  Cascades Developed in Matter, Photon Gas and Magnetic Field   We investigate properties of astrophysical electromagnetic cascades developed
in matter, photon gas and magnetic fields, and discuss similarities and
differences between characteristics of electron-photon showers developed in
these 3 substances.

21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph