Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Conservative difference schemes for one-dimensional flows of polytropic
  gas   The paper considers one-dimensional flows of polytropic (calorically ideal)
gas. These flows include three cases of gas dynamics: plain one-dimensional
flows (one-dimensional space), radially symmetric flows in two-dimensional
space and spherically symmetric flows in three-dimensional space. Starting with
the difference schemes which have conservation laws of mass and energy (as well
as conservation of momentum and the center of mass motion for the plain
one-dimensional flows), we find difference schemes which also have additional
conservation laws for the special values of the adiabatic exponent $\gamma = 1
+ 1 /d $, where $d$ is the space dimension.

18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio