Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hall effect in a strong magnetic field: Direct comparisons of
  compressible magnetohydrodynamics and the reduced Hall magnetohydrodynamic
  equations
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph