Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Energy spectra of cosmic rays accelerated at ultrarelativistic shock
  waves
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys