Abstract

Let M and A be right R-modules. Then, M is called A-Ker projective if there exist projective modules PN , PA and epimorphisms fN : PN −→ N, gA : PA −→ A such that for every homomorphism ψ ∈ HomR(PN , PA), ψ(KerfN ) ≤ KergA. In this paper, we consider the relationships between a projective, a weakly projective, a semi projective and Ker projective modules. Many properties on Ker projective modules were obtained.