Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolution of Structures in Generalized Gravity Theories   A broad class of generalized Einstein's gravity can be cast into Einstein's
gravity with a minimally coupled scalar field using suitable conformal
rescaling of the metric. Using this conformal equivalence between the theories,
we derive the equations for the background and the perturbations, and the
general asymptotic solutions for the perturbations in the generalized
Einstein's gravity from the simple results known in the minimally coupled
scalar field. Results for the scalar and tensor perturbations can be presented
in unified forms. The large scale evolutions for both modes are characterized
by corresponding conserved quantities. We also present the normalization
condition for canonical quantization.

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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph