English

Equivariant bundle gerbes

Differential Geometry 2018-02-02 v2 High Energy Physics - Theory Category Theory

Abstract

We develop the theory of simplicial extensions for bundle gerbes and their characteristic classes with a view towards studying descent problems and equivariance for bundle gerbes. Equivariant bundle gerbes are important in the study of orbifold sigma models. We consider in detail two examples: the basic bundle gerbe on a unitary group and a string structure for a principal bundle. We show that the basic bundle gerbe is equivariant for the conjugation action and calculate its characteristic class; we show also that a string structure gives rise to a bundle gerbe which is equivariant for a natural action of the String 2-group.

Keywords

Cite

@article{arxiv.1506.07931,
  title  = {Equivariant bundle gerbes},
  author = {Michael K. Murray and David Michael Roberts and Danny Stevenson and Raymond F. Vozzo},
  journal= {arXiv preprint arXiv:1506.07931},
  year   = {2018}
}

Comments

v2 35 pages, introduction rewritten, references added, no other substantial changes; v1 33 pages. Comments welcome. License is CC-BY

R2 v1 2026-06-22T10:00:35.718Z