Abstract. A precise title would be: congruences on finitely generated free commutative semigroups, such that the quotient semigroup is finite group-free. Classes modulo such a congruence run parallel to faces of the free semigroup; this permits a description which is more explicit and detailed than Rédei's. Our results may be viewed as constructing all finite group-free commutative semigroups.
AMS Subject Classification
finitely generated free commutative semigroups
Received February 28, 1991 and in revised form November 6, 1991. (Registered under 5529/2009.)