Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X-fluid and viscous fluid in D-dimensional anisotropic integrable
  cosmology   D-dimensional cosmological model describing the evolution of a perfect fluid
with negative pressure (x-fluid) and a fluid possessing both shear and bulk
viscosity in n Ricci-flat spaces is investigated. The second equations of state
are chosen in some special form of metric dependence of the shear and bulk
viscosity coefficients. The equations of motion are integrated and the
dynamical properties of the exact solutions are studied. It is shown the
possibility to resolve the cosmic coincidence problem when the x-fluid plays
role of quintessence and the viscous fluid is used as cold dark matter.

6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci