  Lisa Jeffrey and Frances Kirwan developed an integration theory for
symplectic reductions. That is, given a symplectic manifold with symplectic
group action, they developed a way of pulling the integration of forms on the
reduction back to an integration of group-equivariant forms on the original
space.
  We seek an analogue of the symplectic integration formula as developed by for
the hyperKahler case. This is almost straightforward, but we have to overcome
such obstacles as the lack of a hyper-Darboux theorem and the lack of
compactness in the case of hyperKahler reduction.
