Modules which are self-p-injective relative to projection invariant submodules

Abstract

In this article, we focus on modules M such that every homomorphism from a projection invariant submodule of M to M can be lifted to M . Although such modules share some of the properties of PI -extending (i.e., every projection invariant submodule is essential in a direct summand) modules, it is shown that they form a substantially bigger class of modules.