Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On a non-periodic modified Euler equation: existence and quasi-invariant
  measures   We consider a modified Euler equation on $\mathbb R^2$. We prove existence of
weak global solutions for bounded (and fast decreasing at infinity) initial
conditions and construct Gibbs-type measures on function spaces which are
quasi-invariant for the Euler flow. Almost everywhere with respect to such
measures (and, in particular, for less regular initial conditions), the flow is
shown to be also globally defined.

12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: eess
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ