Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Merging Gravitation with Thermodynamics to Understand Cosmology   We discuss the evolution of the universe in the context of the second law of
thermodynamics from its early stages to the far future. Cosmological
observations suggest that most matter and radiation will be absorbed by the
cosmological horizon. On the local scale, the matter that is not ejected from
our supercluster will collapse to a supermassive black hole and then slowly
evaporate. The history of the universe is that of an approach to the
equilibrium state of the gravitational field.

16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph