Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Oscillatory approach to the singularity in vacuum spacetimes with $T^2$
  isometry   We use qualitative arguments combined with numerical simulations to argue
that, in the approach to the singularity in a vacuum solution of Einstein's
equations with $T^2$ isometry, the evolution at a generic point in space is an
endless succession of Kasner epochs, punctuated by bounces in which either a
curvature term or a twist term becomes important in the evolution equations for
a brief time. Both curvature bounces and twist bounces may be understood within
the context of local mixmaster dynamics although the latter have never been
seen before in spatially inhomogeneous cosmological spacetimes.

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The categories of this paper are: math
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
18
The categories of this paper are: econ
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The categories of this paper are: hep-ex
3
The categories of this paper are: physics