Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Duality for Frames in Krein Spaces   A $J$-frame for a Krein space $\mathcal{H}$ is in particular a frame for
$\mathcal{H}$ (in the Hilbert space sense). But it is also compatible with the
indefinite inner-product of $\mathcal{H}$, meaning that it determines a pair of
maximal uniformly definite subspaces, an analogue to the maximal dual pair
associated to an orthonormal basis in a Krein space. This work is devoted to
study duality for $J$-frames in Krein spaces. Also, tight and Parseval
$J$-frames are defined and characterized.

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The categories of this paper are: cs
27
The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
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The categories of this paper are: ao-sci
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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: nucl-th