Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Rayleigh-Taylor instability for the Verigin problem with and without
  phase transition   Isothermal compressible two-phase flows in a capillary are modeled with and
without phase transition in the presence of gravity, employing Darcy's law for
the velocity field. It is shown that the resulting systems are
thermodynamically consistent in the sense that the available energy is a strict
Lyapunov functional. In both cases, the equilibria with flat interface are
identified. It is shown that the problems are well-posed in an $L_p$-setting
and generate local semiflows in the proper state manifolds. The main result
concerns the stability of equilibria with flat interface, i.e. the
Rayleigh-Taylor instability.

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The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
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The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
25
The categories of this paper are: patt-sol