English

A topological fibrewise fundamental groupoid

Algebraic Topology 2018-02-02 v3 Category Theory

Abstract

It is well-known that for certain local connectivity assumptions the fundamental groupoid of a topological space can be equipped with a topology making it a topological groupoid. In other words, the fundamental groupoid functor can be lifted through the forgetful functor from topological groupoids to groupoids. This article shows that for a map YXY \to X with certain relative local connectivity assumptions, the fibrewise fundamental groupoid can also be lifted to a topological groupoid over the space XX. This allows the construction of a simply-connected covering space in the setting of fibrewise topology, assuming a local analogue of the definition of an ex-space. When applied to maps which are up-to-homotopy locally trivial fibrations the result is a categorified version of a covering space. The fibrewise fundamental groupoid can also be used to define a topological fundamental bigroupoid of a (suitably locally connected) topological space.

Keywords

Cite

@article{arxiv.1411.5779,
  title  = {A topological fibrewise fundamental groupoid},
  author = {David Michael Roberts},
  journal= {arXiv preprint arXiv:1411.5779},
  year   = {2018}
}

Comments

Typos fixed and references/corrections added on referee's and editor's comments. Released under a CC0 license (http://creativecommons.org/publicdomain/zero/1.0/)