Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An inverse boundary value problem for a semilinear wave equation on
  Lorentzian manifolds   We consider an inverse boundary value problem for a semilinear wave equation
on a time-dependent Lorentzian manifold with time-like boundary. The
time-dependent coefficients of the nonlinear terms can be recovered in the
interior from the knowledge of the Neumann-to-Dirichlet map. Either distorted
plane waves or Gaussian beams can be used to derive uniqueness.

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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
3
The categories of this paper are: physics
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The categories of this paper are: q-fin