Counterexamples to the pseudo-Riemannian Lichnerowicz conjecture
  The original version of the paper claimed to disprove the pseudo-Riemannian Lichnerowicz conjecture of D'Ambra and Gromov. However, the argument contains a crucial sign error in the lines following equation (8). 
Andrzej Derdzinski (The Ohio State University)
math.DG