Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact solutions for scalar field cosmology in f(R) gravity   We look for exact solutions in scalar field cosmology. To achieve this we use
$f(R)$ modified gravity with a scalar field and do not specify the the form of
the $f(R)$ function. In particular, we study Friedmann universe assuming that
acceleration of the scalar curvature is negligible. We first present solutions
for special cases and then the general solution. Using initial conditions which
represent the universe at the present epoch, we evaluated the constants of
integration. This allows for the comparison of the scale factor in the new
solutions with that of the $\Lambda CDM$ solution, thereby affecting the age of
the universe in $f(R)$ gravity.

30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph