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July 3, 2008

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 δ=0 :F nF m, it has GL(n,F)×GL(m,F) as objects and F nm worth of arrows from an object to itself. Arrows are linear maps F nF m, and the group of objects acts on them by a kind of composition.

Now, the small thought occurred to me that interchanging the m and n makes little difference. So when I suggested that the Poincaré 2-group was a sub-2-group of the 2-group for n=1 ,m=4 , I might also have said n=4 ,m=1 .

But all this is not so surprising, as this area is quite span-ish and bimodule-esque.

Posted at July 3, 2008 4:35 PM UTC

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