Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Rhombic Patterns Near a Bicritical Point in Periodically Forced Surface
  Waves   We present here a study of selection of rhombic patterns close to a
bicritical point at the onset of primary surface instability in viscous fluids
under two-frequency vertical vibration. Rhombic patterns appear to be natural
at the primary instability in the form of a bicritical point if the ratio of
driving frequencies is selected properly. We present two different patterns
which may be accessible in a Faraday experiment.

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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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The categories of this paper are: math-ph