Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Ultrarelativistic sources in nonlinear electrodynamics
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex