Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Brane world solutions of perfect fluid in the background of a bulk
  containing dust or cosmological constant   The paper presents some solutions to the five dimensional Einstein equations
due to a perfect fluid on the brane with pure dust filling the entire bulk in
one case and a cosmological constant (or vacuum) in the bulk for the second
case. In the first case, there is a linear relationship between isotropic
pressure, energy density and the brane tension, while in the second case, the
perfect fluid is assumed to be in the form of chaplygin gas. Cosmological
solutions are found both for brane and bulk scenarios and some interesting
features are obtained for the chaplygin gas on the brane which are distinctly
different from the standard cosmology in four dimensions.

8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci