Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Invariant Integrability Criterion for the Equations of Hydrodynamical
  Type   Invariant integrability criterion for the equations of hydrodynamical type is
found. This criterion is written in the form of vanishing for some tensor which
is derived from the velocities matrix of hydrodynamical equations.

0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
2
The categories of this paper are: math