Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unitary equivalence of automorphisms of separable C*-algebras   We prove that the automorphisms of any separable C*-algebra that does not
have continuous trace are not classifiable by countable structures up to
unitary equivalence. This implies a dichotomy for the Borel complexity of the
relation of unitary equivalence of automorphisms of a separable unital
C*-algebra: Such relation is either smooth or not even classifiable by
countable structures.

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The categories of this paper are: stat
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The categories of this paper are: q-alg
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: eess