Abstract. This article corrects errors in two previous papers.

AMS Subject Classification (1991): 20M14

Keyword(s): complete, completion, subcomplete, finitely generated commutative semigroup, Ponizovsky family, {\cal K}, -class, Schützenberger monoid, extended Schützenberger functor

Received July 20, 2001. (Registered under 2808/2009.)