Published online by Cambridge University Press: 20 November 2018
We consider minimal left ideals L of the universal semigroup compactification of a topological semigroup S. We show that the enveloping semigroup of L is homeomorphically isomorphic to
if and only if given q ≠ r in
, there is some p in the smallest ideal of
with qp ≠ rp. We derive several conditions, some involving minimal flows, which are equivalent to the ability to separate q and r in this fashion, and then specialize to the case that S =
, and the compactification is
. Included is the statement that some set A whose characteristic function is uniformly recurrent has
.