Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Explorations of the infinite regions of space-time   An important concept in Physics is the notion of an isolated system. It is
used in many different areas to describe the properties of a physical system
which has been isolated from its environment. The interaction with the
`outside' is then usually reduced to a scattering process, in which incoming
radiation interacts with the system, which in turn emits outgoing radiation. In
Einstein's theory of gravitation isolated systems are modeled as asymptotically
flat space-times. They provide the appropriate paradigm for the study of
gravitational waves and their interaction with a material system or even only
with themselves. In view of the emerging era of gravitational wave astronomy,
in which gravitational wave signals from many different astrophysical sources
are detected and interpreted, it is necessary to have a foundation for the
theoretical and numerical treatments of these signals. Furthermore, from a
purely mathematical point of view, it is important to have a full understanding
of the implications of imposing the condition of asymptotic flatness onto
solutions of the Einstein equations. While it is known that there exists a
large class of asymptotically flat solutions of Einstein's equations, it is not
known what the necessary and sufficient conditions at infinity are that have to
be imposed on initial data so that they evolve into regular asymptotically flat
space-times. The crux lies in the region near space-like infinity $i^0$ where
incoming and outgoing radiation `meet'. In this paper we review the current
knowledge and some of the analytical and numerical work that has gone into the
attempt to understand the structure of asymptotically flat space-times near
space-like and null-infinity.

36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
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The categories of this paper are: eess
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex