E-unitary Quasi-orthodox Covers for Quasi-orthodox Semigroups
YU Bing-jun · Journal of Sichuan Normal University · 2012
In this paper,for any quasi-orthodox semigroup S,a semigroupoid C is constructed by using the free group G over(the set) S and a related relational homomorphism.It is proved that G freely transitively acts on C so that there exist a monoid C1 and a semigroup P=C11C1}.Moreover,P is an E-unitary quasi-orthodox semigroup with the maximum group homomorphic image G and S itself is an idempotent-separating homomorphic image of P.Therefore any quasi-orthodox semigroup has an E-unitary cover over a given group.