Twistor Forms on Riemannian Products
  We study twistor forms on products of compact Riemannian manifolds and show that they are defined by Killing forms on the factors. The main result of this note is a necessary step in the classification of compact Riemannian manifolds with non-generic holonomy carrying twistor forms. 
Andrei Moroianu (CMLS-EcolePolytechnique), Uwe Semmelmann (FM)