A Rees matrix semigroup M=.M(T;I,Λ;P)over a monoid T is calld tight if the elements of P lie in the group of units H1 of T.We study the relation-ship between properties of a monoid T and properties of a tight Rees matrix semigroup M=M(T;I,Λ;P).We prove that a tight Rees matrix semigroup M=M(T;I,Λ;P)is isomorphic to a normalised tight Rees matrix semigroup M=M(T;I,Λ;Q).For a tight Rees matrix semigroup M over a weakly superabundant semigroup T,we give the characterization of(～)-good congruence on M.
维普
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