English

Projectively coresolved Gorenstein flat and Ding projective modules

Rings and Algebras 2020-01-28 v1

Abstract

We give necessary and sufficient conditions in order for the class of projectively coresolved Gorenstein flat modules, PGF\mathcal{PGF}, (respectively that of projectively coresolved Gorenstein B\mathcal{B} flat modules, PGFB\mathcal{PGF}_{\mathcal{B}}) to coincide with the class of Ding projective modules (DP)\mathcal{DP}). We show that PGF=DP\mathcal{PGF} = \mathcal{DP} if and only if every Ding projective module is Gorenstein flat. This is the case if the ring RR is coherent for example. We include an example to show that the coherence is a sufficient, but not a necessary condition in order to have PGF=DP\mathcal{PGF} = \mathcal{DP}. We also show that PGF=DP\mathcal{PGF} = \mathcal{DP} over any ring RR of finite weak Gorenstein global dimension (this condition is also sufficient, but not necessary). We prove that if the class of Ding projective modules, DP\mathcal{DP}, is covering then the ring RR is perfect. And we show that, over a coherent ring RR, the converse also holds. We also give necessary and sufficient conditions in order to have PGF=GP\mathcal{PGF} = \mathcal{GP}, where GP\mathcal{GP} is the class of Gorenstein projective modules.

Keywords

Cite

@article{arxiv.2001.09234,
  title  = {Projectively coresolved Gorenstein flat and Ding projective modules},
  author = {Alina Iacob},
  journal= {arXiv preprint arXiv:2001.09234},
  year   = {2020}
}

Comments

17 pages, Communications in Algebra, accepted

R2 v1 2026-06-23T13:20:23.831Z