Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is Hubble's Expansion due to Dark Energy   {\it The universe is expanding} is known (through Galaxy observations) since
1929 through Hubble's discovery ($V = H D$). Recently in 1999, it is found
(through Supernovae observations) that the universe is not simply expanding but
is accelerating too. We, however, hardly know only $4\%$ of the universe. The
Wilkinson Microwave Anisotropy Probe (WMAP) satellite observational data
suggest $73\%$ content of the universe in the form of dark-energy, $23\%$ in
the form of non-baryonic dark-matter and the rest $4\%$ in the form of the
usual baryonic matter. The acceleration of the universe is ascribed to this
dark-energy with bizarre properties (repulsive-gravity). The question is that
whether Hubble's expansion is just due to the shock of big-bang & inflation or
it is due to the repulsive-gravity of dark-energy? Now, it is believed to be
due to dark-energy, say, by re-introducing the once-discarded
cosmological-constant $\Lambda$. In the present paper, it is shown that `the
formula for acceleration due to dark-energy' is (almost) exactly of same-form
as `the acceleration formula from the Hubble's law'. Hence, it is concluded
that: yes, `indeed it is the dark-energy responsible for the Hubble's expansion
too, in-addition to the current on-going acceleration of the universe'.

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The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: econ