Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black hole versus cosmological horizon entropy   The generalized second law of thermodynamics states that entropy always
increases when all event horizons are attributed with an entropy proportional
to their area. We test the generalized second law by investigating the change
in entropy when dust, radiation and black holes cross a cosmological event
horizon. We generalize for flat, open and closed Friedmann-Robertson-Walker
universes by using numerical calculations to determine the cosmological horizon
evolution. In most cases the loss of entropy from within the cosmological
horizon is more than balanced by an increase in cosmological event horizon
entropy, maintaining the validity of the generalized second law of
thermodynamics. However, an intriguing set of open universe models show an
apparent entropy decrease when black holes disappear over the cosmological
event horizon. We anticipate that this apparent violation of the generalized
second law will disappear when solutions are available for black holes embedded
in arbitrary backgrounds.

14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga