Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Dynamical enhancement of nonparaxial effects in the electromagnetic
  field of a vortex electron
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex