Jimmie D. Lawson:
Maximal Ol'shanskii semigroups
Journal of Lie Theory, vol. 4 (1), p. 17-35
In this article we show for
simple complex groups $G_\C$ that if a subsemigroup
$S$ contains a
real form $G$ such that $G$ is not isolated in
$S$, then $S$ contains
a minimal Ol'shanski\u\i\ semigroup and is contained in a maximal
Ol'shanski\u\i\ semigroup. It follows in particular that maximal
Ol'shanski\u\i\ semigroups are maximal semigroups.