  We unify and generalize formulas obtained by Campillo, Delgado and
Gusein-Zade in their series of articles. Positive results are established for
rational and minimally elliptic singularities. By examples and counterexamples
we also try to find the `limits' of these identities. Connections with the
Seiberg-Witten Invariant Conjecture and Semigroup Density Conjecture are
discussed.

Algebraic Geometry