Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Slow-roll inflation in (R+R*4) gravity   We reconsider the toy-model of topological inflation, based on the
R*4-modified gravity. By using its equivalence to the certain scalar-tensor
gravity model in four space-time dimensions, we compute the inflaton scalar
potential and investigate a possibility of inflation. We confirm the existence
of the slow-roll inflation with an exit. However, the model suffers from the
eta-problem that gives rise to the unacceptable value of the spectral index n_s
of scalar perturbations.

32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph
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
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph