Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Zip and velcro bifurcations in competition models in ecology and
  economics   During the last six years or so, a number of interesting papers discussed
systems with line segments of equilibria, planes of equilibria, and with more
general equilibrium configurations. This note draws attention to the fact that
such equilibria were considered previously by Mikl\'os Farkas (1932-2007), in
papers published in 1984-2005. He called zip bifurcations those involving line
segments of equilibria, and velcro bifurcations those involving planes of
equilibria. We briefly describe prototypical situations involving zip and
velcro bifurcations.

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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
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The categories of this paper are: chao-dyn
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The categories of this paper are: physics
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: cs