Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Killing Horizons as Equipotential Hypersurfaces   In this note we present a new proof that Killing horizons are equipotential
hypersurfaces for the electric and the magnetic scalar potential, that makes no
use of gravitational field equations or the assumption about the existence of
bifurcation surface.

7
The categories of this paper are: hep-th
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin