Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An exponential correction to Starobinsky's inflationary model   We analyse $f(R)$ theories of gravity from a dynamical system perspective,
showing how the $R^2$ correction in Starobinsky's model plays a crucial role
from the viewpoint of the inflationary paradigm. Then, we propose a
modification of Starobinsky's model by adding an exponential term in the $f(R)$
Lagrangian. We show how this modification could allow to test the robustness of
the model by means of the predictions on the scalar spectral index $n_s$.

16
The categories of this paper are: stat
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol