GH MOGHADDASI ANGIZAN - Department of Mathematics, Sabzevar Teachers Training University, Sabzevar, Iran

In this paper using the notion of a sequentially dense monomorphism we study the sequential injectivity for acts over a semigroup S. Also we define a closure operator Cs, and then discuss injectivity with respect to Cs-dense monomorphisms. Finally, we show that the notions of s-completeness, sequential injectivity, and sequential absolutely retract coincide.

sequential injective, completeness, absolute retract