  Let H be a Hopf algebra which is a finite module over a central sub-Hopf
algebra R. The ramification behaviour of the maximal ideals of Z(H) with
respect to the subalgebra R is studied. In the case when H is U(g), the
enveloping algebra of a semisimple Lie algebra g, a conjecture of Humphreys is
confirmed. In the case when H is the quantised enveloping algebra of g at a
root of unity we obtain quantum analogues of result of a Mirkovic and Rumynin,
we fully describe the reduced factor algebras over the regular sheet and the
blocks of H are determined.
