Published online by Cambridge University Press: 09 April 2009
A group is called an s-group if it is locally finite and all its Sylow subgroups are abelian. Kovács [4] has shown that, for any positive integer e, the class s
e of all s
-groups of exponent dividing e is a (locally finite) variety. The proof of this relies on the fact that, for any e, there are only finitely many (isomorphism classes of) non-abelian finite simple groups in s
e; and this is a consequence of deep results of Walter and others (see [6]). In [2], Christensen raised the finite basis question for the laws of the varieties s
e. It is easy to establish the finite basis property for an s
e which contains no non-abelian finite simple group; and Christensen gave a finite basis for the laws of the variety s
30, whose only non-abelian finite simple group is PSL(2,5). Here we prove Theorem For any positive integer e, the varietys
ehas a finite basis for its laws.