A Small Observation
Posted by David Corfield
Urs defined the Schreiber 2-group of linear automorphisms of a skeletal Baez-Crans 2-vector space back here. For the space , it has as objects and worth of arrows from an object to itself. Arrows are linear maps , and the group of objects acts on them by a kind of composition.
Now, the small thought occurred to me that interchanging the and makes little difference. So when I suggested that the Poincaré 2-group was a sub-2-group of the 2-group for , I might also have said .
But all this is not so surprising, as this area is quite span-ish and bimodule-esque.