Submission date: 27 March 2018

Abstract:

A countable semigroup is ℵ_0-categorical if it can be characterised, up to isomorphism, by its first order properties. In this paper we continue our investigation into the ℵ_0-categoricity of semigroups. Our main results are a complete classification of ℵ_0-categorical orthodox completely 0-simple semigroups, and descriptions of the ℵ_0-categorical members of certain classes of strong semilattices of semigroups.

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Full text arXiv 1803.10087: pdf, ps.