For a Green biset functor
,
we define the commutant and the center of
and
we study some of their properties and their relationship. This leads in particular to
the main application of these constructions: the possibility of splitting the category of
-modules
as a direct product of smaller abelian categories. We give explicit examples of such
decompositions for some classical shifted representation functors. These
constructions are inspired by similar ones for Mackey functors for a fixed finite
group.
Keywords
biset functor, Green functor, functor category, center