Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Spectral Analysis of the Sixth-order Krall Differential Expression   In this paper, we construct a self-adjoint operator T generated by the
sixth-order Krall differential expression in the extended Hilbert space
L^2(-1,1) + C^2. To obtain T, we apply a new general theory, the so-called
GKN-EM theory, developed recently by Littlejohn and Wellman that extends the
classical Glazman-Krein-Naimark theory using a complex symplectic geometric
approach developed by Everitt and Markus. This work extends earlier studies of
the Krall expression by both Littlejohn and Loveland.

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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: nucl-th