English

Two characterizations of pure injective modules

Commutative Algebra 2007-05-23 v1

Abstract

Let RR be a commutative ring with identity and DD an RR-module. It is shown that if DD is pure injective, then DD is isomorphic to a direct summand of the direct product of a family of finitely embedded modules. As a result, it follows that if RR is Noetherian, then DD is pure injective if and only if DD is isomorphic to a direct summand of the direct product of a family of Artinian modules. Moreover, it is proved that DD is pure injective if and only if there is a family {Tλ}λΛ\{T_\lambda\}_{\lambda\in \Lambda} of RR-algebras which are finitely presented as RR-modules, such that DD is isomorphic to a direct summand of a module of the form ΠλΛEλ\Pi_{\lambda\in \Lambda}E_\lambda where for each λΛ\lambda\in \Lambda, EλE_\lambda is an injective TλT_\lambda-module.

Keywords

Cite

@article{arxiv.math/0509516,
  title  = {Two characterizations of pure injective modules},
  author = {Divaani-Aazar and Esmkhani and Tousi},
  journal= {arXiv preprint arXiv:math/0509516},
  year   = {2007}
}

Comments

8 pages, to appear in Proc. Amer. Math. Soc