This is a correction to the proof of Theorem 2.1 of [1]. An error occurred in the " proof " of Lemma 2.2, which is false. The following should replace the proof of (c) (Sect. II, p. 821ff.), which will correct the proof of the theorem: The initial condition is satisfied by the summand in (2.3) coming from the identity permutation id. So what we have to show is σ =id C r
