Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Point symmetry group of the barotropic vorticity equation   The complete point symmetry group of the barotropic vorticity equation on the
$\beta$-plane is computed using the direct method supplemented with two
different techniques. The first technique is based on the preservation of any
megaideal of the maximal Lie invariance algebra of a differential equation by
the push-forwards of point symmetries of the same equation. The second
technique involves a priori knowledge on normalization properties of a class of
differential equations containing the equation under consideration. Both of
these techniques are briefly outlined.

22
The categories of this paper are: chao-dyn
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
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat