Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Machian General Relativity: a possible solution to the Dark Energy
  problem, and a replacement for Big Bang cosmology   Observations of an apparent acceleration in the expansion rate of the
universe, derived from measurements of high-redshift supernovae, have been used
to support the hypothesis that the universe is permeated by some form of dark
energy. We show that an alternative cosmological model, based on a linearly
expanding universe with Omega=1, can fully account for these observations. This
model is also able to resolve the other problems associated with the standard
Big Bang model. A scale-invariant form of the field equations of General
Relativity is postulated, based on the replacement of the Newtonian
gravitational constant by an formulation based explicitly on Mach's principle.
We derive the resulting dynamical equations, and show that their solutions
describe a linearly expanding universe. Potential problems with non-zero
divergencies in the modified field equations are shown to be resolved by
adopting a radically different definition of time, in which the unit of time is
a function of the scale-factor. We observe that the effects of the modified
field equations are broadly equivalent to a Newtonian gravitational constant
that varies both in time and in space, and show that this is also equivalent to
Varying Speed of Light (VSL) theories using a standard definition of time. Some
of the implications of this observation are discussed in relation to Black
Holes, Planck scale phenomena, and the ultimate fate of the Universe.

18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex