Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Density of Schr\"odinger Weyl-Titchmarsh m functions on Herglotz
  functions   We show that the Herglotz functions that arise as Weyl-Titchmarsh $m$
functions of one-dimensional Schr\"odinger operators are dense in the space of
all Herglotz functions with respect to uniform convergence on compact subsets
of the upper half plane. This result is obtained as an application of de
Branges theory of canonical systems.

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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: hep-lat