Rational singularities and almost split sequences

The main aim of this paper is to relate almost split sequences to singularity theory by showing that the McKay quiver built from the finite-dimensional representations of a finite subgroup G G of GL ⁡ (2, C) GL (2, {C}), where C {C} is the complex numbers, is isomorphic to the A R AR quiver of the reflexive modules of the quotient singularity associated with G G.