Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Halmos-von Neumann theorem for actions of general groups   We give a new categorical approach to the Halmos-von Neumann theorem for
actions of general topological groups. As a first step, we establish that the
categories of topological and measure-preserving irreducible systems with
discrete spectrum are equivalent. This allows to prove the Halmos-von Neumann
theorem in the framework of topological dynamics. We then use the Pontryagin
and Tannaka-Krein duality theories to obtain classification results for
topological and then measure-preserving systems with discrete spectrum. As a
byproduct, we obtain a complete isomorphism invariant for compactifications of
a fixed topological group.

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The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: astro-ph