An explicit String bundle
by David Roberts
Abstract: If the structure group of the tangent bundle of a manifold lifts to the 3-connected cover String(n) of O(n), then we say the manifold is string. This group is never a finite-dimensional Lie group, but has a reasonably simple construction as a strict Fr\'echet-Lie 2-group. One can then describe the analogues of transition functions with values in a 2-group. In this talk I will give an explicit set of transition functions for String(3)-bundle, which turn out to be rational functions.