Anomalies in N=2 supersymmetric non-linear sigma models on compact   Kahler Ricci-flat target spaces
  We analyse with the algebraic, regularisation independent, cohomological B.R.S. methods, the renormalisability of torsionless N=2 supersymmetric non-linear sigma models built on Kahler spaces. Surprisingly enough with respect to the common wisdom, we obtain an anomaly candidate, at least in the compact Ricci-flat case. In the compact homogeneous Kahler case, as expected, the anomaly candidate disappears. 
Guy Bonneau