Cotangent cohomology of rational surface singularities
  We show that the number of generators of the n-th cotangent cohomology group (n >=2) is the same for all rational surface singularities Y. For a large class of rational surface singularities, including quotient singularities, this number is also the dimension. For them we obtain an explicit formula for the corresponding Poincare series. 
Klaus Altmann (Berlin), Jan Stevens (G\"oteborg)