Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovering the Kerr and Kerr-Schild metrics   An historical account of the reasoning that led to the discovery of the Kerr
and Kerr-Schild metrics in 1963-1964, and their physical interpretation as
rotating black holes, is presented.

16
The categories of this paper are: stat
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci