This is a preview. Log in through your library . Abstract A group G end its global semigroup Glb G is considered. Every congruence relation in the group G induces a congruence relation in the ...

Let S be a regular semigroup and let ρ be a congruence relation on S. The kernel of ρ, in notation $\ker \rho$, is the union of the idempotent ρ-classes. The trace of ρ, in notation tr ρ, is the ...