Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Solutions of the Euler equations and stationary structures in an
  inviscid fluid   The Euler equations describing two-dimensional steady flows of an inviscid
fluid are studied. These equations are reduced to one equation for the stream
function and then, using the Hirota function, solutions of three nonlinear
elliptic equations are found. %: Sine-Gordon, Sinh-Gordon and Tzitz\'{e}ica.
The solutions found are interpreted as sources in a rotating fluid, jets,
chains of sources and sinks, vortex structures. We propose a new simple method
for constructing solutions in the form of rational expressions of elliptic
functions. It is shown that the flux of fluid across a closed curve is
quantized in the case of the elliptic Sin-Gordon equation.

0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat