On hypersurface quotient singularities of dimension 4

Abstract

We consider geometrical problems on Gorenstein hypersurface orbifolds of dimension n≥4 through the theory of Hilbert scheme of group orbits. For a linear special group G acting on ℂn, we study the G-Hilbert scheme HilbG(ℂn) and crepant resolutions of ℂn/G for G the A-type abelian group Ar(n). For n=4, we obtain the explicit structure of HilbAr(4)(ℂ4). The crepant resolutions of ℂ4/Ar(4) are constructed through their relation with HilbAr(4)(ℂ4), and the connections between these crepant resolutions are found by the “flop” procedure of 4-folds. We also make some primitive discussion on HilbG(ℂn) for G the alternating group 𝔄n+1 of degree n+1 with the standard representation on ℂn; the detailed structure of Hilb𝔄4(ℂ3) is explicitly constructed.