English

Homotopy classification of gerbes

Algebraic Topology 2007-05-23 v1 Algebraic Geometry

Abstract

Gerbes are locally connected presheaves of groupoids. They are classified up to local weak equivalence by path components in a 2-cocycle category taking values in all sheaves of groups, their isomorphisms and homotopies. If F is a full presheaf of sheaves of groups, isomorphisms and homotopies, then [*,BF] is isomorphic to equivalence classes of gerbes locally equivalent to groups appearing in F. Giraud's non-abelian cohomology object of equivalence classes of gerbes with band L is isomorphic to morphisms in the homotopy category from the point * to the homotopy fibre over L for a map defined on BF and taking values in the classifying space for the stack completion of the fundamental groupoid of F.

Keywords

Cite

@article{arxiv.math/0605200,
  title  = {Homotopy classification of gerbes},
  author = {J. F. Jardine},
  journal= {arXiv preprint arXiv:math/0605200},
  year   = {2007}
}
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