Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Topological T-duality and T-folds   We explicitly construct the C*-algebras arising in the formalism of
Topological T-duality due to Mathai and Rosenberg from string-theoretic data in
several key examples. We construct a continuous-trace algebra with an action of
${\mathbb R}^d$ unique up to exterior equivalence from the data of a smooth
${\mathbb T}^d$-equivariant gerbe on a trivial bundle $X = W \times {\mathbb
T}^d$. We argue that the `noncommutative T-duals' of Mathai and Rosenberg,
should be identified with the nongeometric backgrounds well-known in string
theory. We also argue that the crossed-product C*-algebra ${\mathcal A}
\rtimes_{\alpha|_{\KZ^d}} {\mathbb Z}^d$ should be identified with the T-folds
of Hull which geometrize these backgrounds.
  We identify the charge group of D-branes on T-fold backgrounds in the
C*-algebraic formalism of Topological T-duality. We also study D-branes on
T-fold backgrounds. We show that the $K$-theory bundles studied by Echterhoff,
Nest and Oyono-Oyono give a natural description of these objects.

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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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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: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex