IMI/Publicaţii/QRS/Ediţii/QRS v.21, n.2 (30), 2013/

Clifford congruences on perfect semigroups

Authors: R. S. Gigon


We describe the least Clifford congruence on a some idempotent-surjective perfect semigroup S. In addition, a characterization of all Clifford congruences on such a semigroup is given. Furthermore, we find necessary and sufficient conditions for such congruences to be idempotent pure or E-unitary. Moreover, we give a full description of all USG-congruences on some idempotent-surjective perfect semigroup.


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