Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-singular modified gravity unifying inflation with late-time
  acceleration and universality of viscous ratio bound in F(R) theory   The review of basic cosmological properties of four-dimensional F(R)-gravity,
including FRW equations of motion and its accelerating solutions, generalized
fluid and scalar-tensor representation of the theory is done. Cosmological
reconstruction equation is written and conditions for stability of cosmological
solution are discussed. The overview of realistic F(R)-models unifying
inflation with dark energy epoch is made. The avoidance of finite-time future
singularities in such theories via the introduction of R^2-term is studied. New
realistic non-singular F(R)-gravity unifying early-time inflation with
late-time acceleration is presented. The exit from inflationary era in such
model may be caused by the gravitational scenario. It is demonstrated that
five-dimensional F(R)-gravity considered as non-perturbative stringy effective
action leads to universal relation for viscous bound ratio.

2
The categories of this paper are: math
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol