English

A Construction of String 2-Group Models using a Transgression-Regression Technique

Differential Geometry 2012-12-18 v2 Algebraic Topology

Abstract

In this note we present a new construction of the string group that ends optionally in two different contexts: strict diffeological 2-groups or finite-dimensional Lie 2-groups. It is canonical in the sense that no choices are involved; all the data is written down and can be looked up (at least somewhere). The basis of our construction is the basic gerbe of Gawedzki-Reis and Meinrenken. The main new insight is that under a transgression-regression procedure, the basic gerbe picks up a multiplicative structure coming from the Mickelsson product over the loop group. The conclusion of the construction is a relation between multiplicative gerbes and 2-group extensions for which we use recent work of Schommer-Pries.

Keywords

Cite

@article{arxiv.1201.5052,
  title  = {A Construction of String 2-Group Models using a Transgression-Regression Technique},
  author = {Konrad Waldorf},
  journal= {arXiv preprint arXiv:1201.5052},
  year   = {2012}
}

Comments

25 pages; v2 is the published version (with some minor corrections)

R2 v1 2026-06-21T20:09:05.498Z