On the existence of bibundles
Abstract
We consider the existence of bibundles, in other words locally trivial principal G spaces with commuting left and right G actions. We show that their existence is closely related to the structure of the group Out(G) of outer automorphisms of G. We also develop a classifying theory for bibundles. The theory is developed in full generality for (H, G) bibundles for a crossed module (H, G) and we show with examples the close links with loop group bundles.




