Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The Effective Lorentzian and Teleparallel Spacetimes Generated by a Free
  Electromagnetic Field
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
19
The categories of this paper are: eess