Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Existence of steady states for the Maxwell-Schr\"odinger-Poisson system:
  exploring the applicability of the concentration-compactness principle
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas