A 2-group construction from an extension of the 3-loop group ${\Omega }^{3}G$

Jouko Mickelsson, Ossi Niemimäki

We define a 3-loop group ${\Omega }^{3}G$ as a subgroup of smooth maps from a 3-ball to a Lie group $G$, and then construct a 2-group based on an automorphic action on the Mickelsson-Faddeev…