  We show that the (co)endomorphism algebra of a sufficiently separable "fibre"
functor into Vect_k, for k a field of characteristic 0, has the structure of
what we call a "unital" von Neumann core in Vect_k. For Vect_k, this particular
notion of algebra is weaker than that of a Hopf algebra, although the
corresponding concept in Set is again that of a group.
