Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classification of near-horizon geometries of extremal black holes   Any spacetime containing a degenerate Killing horizon, such as an extremal
black hole, possesses a well-defined notion of a near-horizon geometry. We
review such near-horizon geometry solutions in a variety of dimensions and
theories in a unified manner. We discuss various general results including
horizon topology and near-horizon symmetry enhancement. We also discuss the
status of the classification of near-horizon geometries in theories ranging
from vacuum gravity to Einstein-Maxwell theory and supergravity theories.
Finally, we discuss applications to the classification of extremal black holes
and various related topics. Several new results are presented and open problems
are highlighted throughout.

16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an