Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: An implicit ODE-based numerical solver for the simulation of the
  Heisenberg-Euler equations in 3+1 dimensions
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex