The aim of this short paper is to provide some positive evidence about the following conjecture, of which the result mentioned above is just a special case.
CONJECTURE. Let G be a group and a be a cocycle of G. Then either G is of a-central type or Proj(G, a) contains at least two elements of the same degree.The reader will discover that groups of a-central type play an important part in our investigation of the conjecture, which we are able to verify in a number of cases; most notably when G is supersoluble or has odd order.