Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-stationary adiabatic filtration of gases in porous media   A non-stationary isentropic filtration of gases in porous media is
considered. Thermodynamics in terms of contact and symplectic geometries is
briefly discussed. Algebra of symmetries for the PDE system is found, and the
classification of media with respect to admissible symmetries is given.
Solution for one class of media is found and the phase transitions for this
solution are studied. Keywords: gas filtration, porous media, symmetry algebra,
phase

25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph