Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Viable Palatini-f(R) cosmologies with generalized dark matter   We study the formation of large-scale structure in universes dominated by
dark matter and driven to accelerated expansion by f(R) gravity in the Palatini
formalism. If the dark matter is cold, practically all of these models are
ruled out because they fail to reproduce the observed matter power spectrum. We
point out that if the assumption that dark matter is perfect and pressureless
at all scales is relaxed, nontrivial alternatives to a cosmological constant
become viable within this class of modified gravity models.

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The categories of this paper are: cs
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio