Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instability of strong regular reflection and counterexamples to the
  detachment criterion   We consider a particular instance of reflection of shock waves in
self-similar compressible flow. We prove that local self-similar regular
reflection (RR) cannot always be extended into a global flow. Therefore the
detachment criterion is not universally correct. More precisely, consider the
following "angle condition": the tangent of the strong-type reflected shock
meets the opposite wall at a sharp or right downstream side angle. In cases
where the condition is violated and the weak-type reflected shock is transonic,
we show that global RR does not exist. Combined with earlier work we have shown
that none of the classical criteria for RR-MR transition is universally
correct. A new criterion is proposed. Moreover, we have shown that strong-type
RR is unstable, in the sense that global RR cannot persist under perturbations
to one side. This yields a definite answer to the weak-strong problem because
earlier work shows stability of weak RR in the same sense.

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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: eess
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The categories of this paper are: gr-qc