$$\aleph _0$$-categoricity of semigroups II
Thomas J. Gregson · Semigroup Forum · 2020
Abstract A countable semigroup is $$\aleph _0$$ ℵ0 -categorical if it can be characterised, up to isomorphism, by its first-order properties. In this paper we continue our investigation into the $$\aleph _0$$ ℵ0 -categoricity of semigroups. Our main results are a complete classification of $$\aleph _0$$ ℵ0 -categorical orthodox completely 0-simple semigroups, and descriptions of the $$\aleph _0$$ ℵ0 -categorical members of certain classes of strong semilattices of semigroups.