Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Approximation properties and entropy estimates for crossed products by
  actions of amenable discrete quantum groups   We construct explicit approximating nets for crossed products of C*-algebras
by actions of discrete quantum groups. This implies that C*-algebraic
approximation properties such as nuclearity, exactness or completely bounded
approximation property are preserved by taking crossed products by actions of
amenable discrete quantum groups. We also show that the noncommutative
topological entropy of a transformation commuting with the quantum group action
does not change when we pass to the canonical extension to the crossed product.
Both these results are extended to twisted crossed products via a stabilisation
trick.

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The categories of this paper are: patt-sol
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The categories of this paper are: econ
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: alg-geom
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: supr-con