Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral theory of elliptic differential operators with indefinite
  weights   The spectral properties of a class of non-selfadjoint second order elliptic
operators with indefinite weight functions on unbounded domains $\Omega$ are
investigated. It is shown that under an abstract regularity assumption the
nonreal spectrum of the associated elliptic operator in $L^2(\Omega)$ is
bounded. In the special case that $\Omega=R^n $decomposes into subdomains
$\Omega_+$ and $\Omega_-$ with smooth compact boundaries and the weight
function is positive on $\Omega_+$ and negative on $\Omega_-$, it turns out
that the nonreal spectrum consists only of normal eigenvalues which can be
characterized with a Dirichlet-to-Neumann map.

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The categories of this paper are: physics
32
The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: adap-org