Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Viscous dark fluid   The unified dark energy and dark matter model within the framework of a model
of a continuous medium with bulk viscosity (dark fluid) is considered. It is
supposed that the bulk viscosity coefficient is an arbitrary function of the
Hubble parameter. The choice of this function is carried out under the
requirement to satisfy the observational data from recombination ($z\approx
1000$) till present time.

12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys