Characterization of the automorphisms having the lifting property in the category of Abelian -groups.
Characterization of the automorphisms of an Abelian group having the extension property. (Caractérisation des automorphismes d'un groupe abélien ayant la propriété de l'extension.)
Characterization of the inessential endomorphisms in the category of Abelian group.
An endomorphism f of an Abelian group A is said to be inessentia! (in the category of Abelian groups) if it can be extended to an endomorphism of any Abelian group which contains A as a subgroup. In this paper we show that f is as above if and only if (f - v idA)(A) is contained in the rnaximal divisible subgroup of A for some v belonging to Z.
Page 1