Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dual-band general Toeplitz operators   We relate dual-band general Toeplitz operators to block truncated Toeplitz
operators and, via equivalence after extension, with Toeplitz operators with $4
\times 4$ matrix symbols. We discuss their norm, their kernel, Fredhomlness,
invertibility and spectral properties in various situations, focusing on the
spectral properties of the dual-band shift, which turns out to be considerably
complex, leading to new and nontrivial connections with the boundary behaviour
of the associated inner function.

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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: gr-qc