A CLASS OF VARIETIES OF INVERSE-SEMIGROUPS

Let Wr(U, V) denote the variety of inverse semigroups generated by wreath products of semigroups in U with semigroups in V, where U and V are varieties of inverse semigroups. In this note we provide a description of the fully invariant congruence on the free inverse semigroup corresponding to Wr(U, V) in terms of the fully invariant congruences corresponding to U and V. Some properties of varieties of this form are then presented. © 1991.