Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Big Bang is a Coordinate Singularity for $k = -1$ Inflationary FLRW
  Spacetimes   We show that the big bang is a coordinate singularity for a large class of $k
= -1$ inflationary FLRW spacetimes which we have dubbed 'Milne-like.' By
introducing a new set of coordinates, the big bang appears as a past boundary
of the universe where the metric is no longer degenerate -- a result which has
already been investigated in the context of vacuum decay [12]. We generalize
their results and approach the problem from a more mathematical perspective.
Similar to how investigating the geometrical properties of the $r = 2m$ event
horizon in Schwarzschild led to a better understanding of black holes, we
believe that investigating the geometrical properties of the big bang
coordinate singularity for Milne-like spacetimes could lead to a better
understanding of cosmology. We show how the mathematics of these spacetimes may
help illuminate certain issues associated with dark energy, dark matter, and
the universe's missing antimatter.

23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
1
The categories of this paper are: cs