Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Cauchy Horizon in Higher-derivative Gravity Theories   A class of exact solutions of the field equations with higher derivative
terms is presented when the matter field is a pressureless null fluid plus a
Maxwellian static electric component. It is found that the stable solutions are
black holes in anti de Sitter background. The issue of the stability of the
Cauchy horizon is discussed.

16
The categories of this paper are: stat
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn