Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Untwisting a twisted Calabi-Yau algebra   Twisted Calabi-Yau algebras are a generalisation of Ginzburg's notion of
Calabi-Yau algebras. Such algebras A come equipped with a modular automorphism
\sigma \in Aut(A), the case \sigma = id being precisely the original class of
Calabi-Yau algebras. Here we prove that every twisted Calabi-Yau algebra may be
extended to a Calabi-Yau algebra. More precisely, we show that if A is a
twisted Calabi-Yau algebra with modular automorphism \sigma, then the smash
product algebras A \rtimes_\sigma N and A \rtimes_\sigma Z are Calabi-Yau.

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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-fin