Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gradings on classical central simple real Lie algebras   For any abelian group $G$, we classify up to isomorphism all $G$-gradings on
the classical central simple Lie algebras, except those of type $D_4$, over the
field of real numbers (or any real closed field).

13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ