Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Open cosmologies with rotation   We study a rotating and expanding, Godel type metric, originally considered
by Korotkii and Obukhov, showing that, in the limit of large times and nearby
distances, it reduces to the open metric of Friedmann. In the epochs when
radiation or dust matter dominate the energy density, our solutions are similar
to the isotropic ones and, in what concerns processes occurring at small times,
the rotation leads only to higher order corrections. At large times, the
solution is dominated by a decaying positive cosmological term, with negative
pressure, and necessarily describes a quasi-flat universe if the energy
conditions have to be satisfied. The absence of closed time-like curves
requires a superior limit for the global angular velocity, which appears as a
natural explanation for the observed smallness of the present rotation. The
conclusion is that the introduction of a global rotation, in addition to be
compatible with observation, can enrich the standard model of the Universe,
explaining issues like the origin of galaxies rotation and the quasi-flatness
problem.

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The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex