On locally compact semitopological O-bisimple inverse ω-semigroups

Abstract We describe the structure of Hausdorff locally compact semitopological O-bisimple inverse ω- semigroups with compact maximal subgroups. In particular, we show that a Hausdorff locally compact semitopological O-bisimple inverse ω-semigroup with a compact maximal subgroup is either compact or it is a topological sum of its H-classes. We describe the structure of Hausdorff locally compact semitopological O-bisimple inverse ω-semigroups with a monothetic maximal subgroups. We show the following dichotomy: a T1 locally compact semitopological Reilly semigroup (B(Z+, θ)0, τ) over the additive group of integers Z+, with adjoined zero and with a non-annihilating homomorphism is either compact or discrete. At the end we establish some properties of the remainder of the closure of the discrete Reilly semigroup B(Z+, θ) in a semitopological semigroup.