Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: P-Operators on Hilbert Spaces   A real square matrix $A$ is called a P-matrix if all its principal minors are
positive. Using the sign non-reversal property of matrices, the notion of
P-matrix has been recently extended by Kannan and Sivakumar to
infinite-dimensional Banach spaces relative to a given Schauder basis.
Motivated by their work, we discuss P-operators on separable real Hilbert
spaces. We also investigate P-operators relative to various orthonormal bases.

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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: math-ph