Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonexpanding impulsive gravitational waves with an arbitrary
  cosmological constant   Exact solutions for nonexpanding impulsive waves in a background with nonzero
cosmological constant are constructed using a `cut and paste' method. These
solutions are presented using a unified approach which covers the cases of de
Sitter, anti-de Sitter and Minkowski backgrounds. The metrics are presented in
continuous and distributional forms, both of which are conformal to the
corresponding metrics for impulsive pp-waves, and for which the limit as
$\Lambda\to 0$ can be made explicitly.

7
The categories of this paper are: hep-th
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio