Deformation theory of scalar-flat Kähler ALE surfaces

Abstract

We prove a Kuranishi-type theorem for deformations of complex structures on ALE K\"ahler surfaces. This is used to prove that for any scalar-flat K\"ahler ALE surface, all small deformations of complex structure also admit scalar-flat K\"ahler ALE metrics. A local moduli space of scalar-flat K\"ahler ALE metrics is then constructed, which is shown to be universal up to small diffeomorphisms (that is, diffeomorphisms which are close to the identity in a suitable sense). A formula for the dimension of the local moduli space is proved in the case of a scalar-flat K\"ahler ALE surface which deforms to a minimal resolution of $\Bbb{C}^2/\Gamma$, where $\Gamma$ is a finite subgroup of ${\rm U}(2)$ without complex reflections.