Abstract (EN):
Let Sl denote the class of all finite semilattices and let Sln be the pseudovariety of semigroups generated by all semidirect products of n finite Semilattices. The main result of this paper shows that, for every n ¿ 3, Sln is not finitely based. Nevertheless, a simple basis of identities is described for each Sln. We also show that Sln is generated by a semigroup with 2n generators but, except for n ¿ 2, we do not know whether the bound 2n is optimal. © 1991.
Language:
English
Type (Professor's evaluation):
Scientific