On $R$-Coneat Injective Modules and Generalizations

Both the classes of $R$-coneat injective modules and its superclass, pure Baer injective modules, are shown to be preenveloping. The former class is contained in another one, namely, self coneat injectives, i.e. modules $M$ for which every map $f$ from a coneat left ideal of $R$ into $M$, whose kernel contains the annihilator of some element in $M$, is induced by a homomorphism $R\to M$. Certain types of rings are characterized by properties of the above modules. For instance, a commutative ring $R$ is von Neuman regular if and only if all self coneat injective $R$-modules are quasi injective.