Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Modification of relativistic beam fields under the influence of external
  conducting and ferromagnetic flat boundaries
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess