AbstractWe explicitly describe infinitesimal deformations of cyclic quotient
singularities that satisfy one of the deformation conditions introduced by
Wahl, Kollár–Shepherd-Barron (KSB) and Viehweg. The conclusion is that in many
cases these three notions are different from each other. In particular, we see that
while the KSB and the Viehweg versions of the moduli space of surfaces of
general type have the same underlying reduced subscheme, their
infinitesimal structures are different.
Infinitesimal deformations of quotient surface singularities
