Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Geometric study of gas behavior in a one-dimensional nozzle (the case of
  the van der Waals gas   We construct a three-component system of PDEs describing dynamics of van der
Walls gas in one-dimensional nozzle. The group of conservation laws for this
system is described. We also ompute the Lie algebras of point symmetries and
present group classification. Exact invariant solutions are discussed.

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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: eess
37
The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
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The categories of this paper are: econ
26
The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex