Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A matrix characterization of boundary representations of positive
  matrices in the Hardy space   Spectral measures give rise to a natural harmonic analysis on the unit disc
via a boundary representation of a positive matrix arising from a spectrum of
the measure. We consider in this paper the reverse: for a positive matrix in
the Hardy space of the unit disc we consider which measures, if any, yield a
boundary representation of the positive matrix. We introduce a potential
characterization of those measures via a matrix identity and show that the
characterization holds in several important special cases.

30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin