Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Crossed Module Bundle Gerbes; Classification, String Group and
  Differential Geometry   We discuss nonabelian bundle gerbes and their differential geometry using
simplicial methods. Associated to any crossed module there is a simplicial
group NC, the nerve of the 1-category defined by the crossed module and its
geometric realization |NC|. Equivalence classes of principal bundles with
structure group |NC| are shown to be one-to-one with stable equivalence classes
of what we call crossed module gerbes bundle gerbes. We can also associate to a
crossed module a 2-category C'. Then there are two equivalent ways how to view
classifying spaces of NC-bundles and hence of |NC|-bundles and crossed module
bundle gerbes. We can either apply the W-construction to NC or take the nerve
of the 2-category C'. We discuss the string group and string structures from
this point of view. Also a simplicial principal bundle can be equipped with a
simplicial connection and a B-field. It is shown how in the case of a
simplicial principal NC-bundle these simplicial objects give the bundle gerbe
connection and the bundle gerbe B-field.

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The categories of this paper are: funct-an
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The categories of this paper are: eess
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The categories of this paper are: astro-ph
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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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: econ
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat