Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Characteristic form of boost-invariant and cylindrically non-symmetric
  hydrodynamic equations   It is shown that the boost-invariant and cylindrically non-symmetric
hydrodynamic equations for baryon-free matter may be reduced to only two
coupled differential equations. In the case where the system exhibits the
cross-over phase transition, the standard numerical methods may be applied to
solve these equations and the proposed scheme allows for a very convenient
analysis of the cylindrically non-symmetric hydrodynamic expansion.

1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an