Modularity of the lattice of congruences of a regular ω-semigroup
C. Bonzini, A. Cherubini · Proceedings of the Edinburgh Mathematical Society · 1990
In this paper a characterization of the regular ω-semigroups whose congruence lattice is modular is given. The characterization obtained for such semigroups generalizes the one given by Munn for bisimple ω-semigroups and completes a result of Baird dealing with the modularity of the sublattice of the congruence lattice of a simple regular ω-semigroup consisting of congruences which are either idempotent separating or group congruences.