Extensions of Baer and Principally Projective Modules

Abstract

In this note, we investigate extensions of Baer and principally projective modules. Let R be an arbitrary ring with identity and M a right R-module. For an abelian module M, we show that M is Baer (resp. principally projective) if and only if the polynomial extension of M is Baer (resp. principally projective) if and only if the power series extension of M is Baer (resp. principally projective) if and only if the Laurent polynomial extension of M is Baer (resp. principally projective) if and only if the Laurent power series extension of M is Baer (resp. principally projective).