Natural G-Constellation Families
  Let G be a finite subgroup of GL_n(C). G-constellations are a scheme-theoretic generalization of orbits of G in C^n. We study flat families of G-constellations parametrised by an arbitrary resolution of the quotient space C^n/G. We develop a geometrical naturality criterion for such families, and show that, for an abelian G, the number of the equivalence classes of these natural families is finite.   The main intended application is the derived McKay correspondence. 
Timothy Logvinenko