Exceptional quotient singularities

On Exceptional Quotient Singularities

We study four-dimensional and five-dimensional exceptional quotient singularities.

Motivic Integration and Quotient Singularities

Geometry of splice-quotient singularities

We obtain a new important basic result on splice-quotient singularities in an elegant combinatorial-geometric way: every level of the divisorial filtration of the ring of functions is generated by monomials of the defining coordinate functions. The elegant way is the language of of line bundles based on Okuma’s description of the function ring of the universal abelian cover. As an easy applicat...

Wild Quotient Singularities of Surfaces

Let (B,MB) denote a regular local ring of dimension two. Let H be a finite cyclic group acting on B, and let Z := Spec(B). Assume that the action of H on Spec(B) is free off the closed point, and thatMB is the only singular point of Z. Let f : X → Z be a resolution of the singularity, minimal with the property that the irreducible components of f(MB ) are smooth with normal crossings. Such a re...

The Versal Deformation of Cyclic Quotient Singularities

We describe the versal deformation of two-dimensional cyclic quotient singularities in terms of equations, following Arndt, Brohme and Hamm. For the reduced components the equations are determined by certain systems of dots in a triangle. The equations of the versal deformation itself are governed by a different combinatorial structure, involving rooted trees. One of the goals of singularity th...