Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Periodic solitons for the elliptic-elliptic focussing Davey-Stewartson
  equations   We consider the elliptic-elliptic, focussing Davey-Stewartson equations,
which have an explicit bright line soliton solution. The existence of a family
of periodic solitons, which have the profile of the line soliton in the
longitudinal spatial direction and are periodic in the transverse spatial
direction, is established using dynamical systems arguments. We also show that
the line soliton is linearly unstable with respect to perturbations in the
transverse direction.

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The categories of this paper are: hep-ph
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The categories of this paper are: econ
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The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: alg-geom