Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constraining Newtonian stellar configurations in f(R) theories of
  gravity   We consider general metric $f(R)$ theories of gravity by solving the field
equations in the presence of a spherical static mass distribution by analytical
perturbative means. Expanding the field equations systematically in $\cO(G)$,
we solve the resulting set of equations and show that $f(R)$ theories which
attempt to solve the dark energy problem very generally lead to
$\gamma_{PPN}=1/2$ in the solar system. This excludes a large class of theories
as possible explanations of dark energy. We also present the first order
correction to $\gamma_{PPN}$ and show that it cannot have a significant effect.

2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas