Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Fluid dynamics at arbitrary Knudsen on a base of Alexeev-Boltzmann
  equation: sound in a rarefied gas
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin