Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adjoint characteristics for Eulerian two-dimensional supersonic flow   The formal expressions, in terms of local flow variables, defining the
adjoint characteristic curves, and the associated compatibility relationships
satisfied along them, are formally derived in the case of a supersonic flow
governed by the compressible Euler equations in two dimensions. These findings
extend their well-known counterparts for the direct system, and should serve
analytical and possibly numerical studies of the perfect-flow model with
respect to adjoint fields or sensitivity questions. Beside the analytical
theory, the results are demonstrate by the numerical integration over a very
fine grid of the compatibility relationships for discrete flow-fields and
dual-consistent adjoint fields.

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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin