Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Geometrical properties of trapped surfaces and apparent horizons   In this paper, we perform a detailed investigation on the various geometrical
properties of trapped surfaces and the boundaries of trapped region in general
relativity. This treatment extends earlier work on LRS II spacetimes to a
general 4 dimensional spacetime manifold. Using a semi-tetrad covariant
formalism, that provides a set of geometrical and matter variables, we
transparently demonstrate the evolution of the trapped region and also extend
Hawking's topology theorem to a wider class of spacetimes. In addition, we
perform a stability analysis for the apparent horizons in this formalism,
encompassing earlier works on this subject. As examples, we consider the
stability of MOTS of the Schwarzschild geometry and Oppenheimer-Snyder
collapse.

13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs