Published online by Cambridge University Press: 09 April 2009
This paper extends results on product varieties of groups to inverse semigroups. We show that if is a variety of groups and
any inverse semigroup variety, then
∘
is a variety. We give a characterization of the identities of
∘
in terms of the identities of
and of
We show that if
does not contain the variety of all groups then it has uncountably many supervarieties. Finally we show that if
is another variety of groups then
Subject classifiaction (Amer. Math. Soc. (MOS) 1970): 20 M 05.