Acyclic complexes of FP-injective modules over Ding-Chen rings
James Gillespie
TL;DR
The work introduces a general method to merge two cotorsion pairs into an abelian model structure and applies it to left $R$-modules over a left coherent ring $R$, with fibrant objects generated by the weakly Ding injective class and characterized as cycles $Z_0X$ of acyclic complexes of $FP$-injective modules. In the Ding-Chen setting, these fibrant cycles coincide with cycles of acyclic FP-injectives, enabling a detailed description of the stable module category in terms of Gorenstein FP-pro-injective modules. The authors develop non-hereditary model constructions for derived categories by lifting non-hereditary cotorsion pairs to chain complexes, and they establish several dualities, including a complete duality between $\mathcal Z$ and Gorenstein flat modules via character modules. The results yield new abelian models and representations of derived and stable categories, extend Iacob’s weakly Ding injective framework, and connect FP-injective theory to broader Gorenstein homological structures, providing practical tools for studying Ding-Chen rings and their associated homotopy theories.
Abstract
We present a new method for combining two cotorsion pairs to obtain an abelian model structure and we apply it to construct and study a new model structure on left $R$-modules over a left coherent ring $R$. Its class of fibrant objects is generated by the weakly Ding injective $R$-modules, a class of modules recently studied by Iacob. We give several characterizations of the fibrant modules, one being that they are the cycle modules of certain acyclic complexes of FP-injective (i.e., absolutely pure) $R$-modules. In the case that $R$ is a Ding-Chen ring, we show that they are precisely the modules appearing as cycles of acyclic complexes of FP-injectives. This leads to a new description of the stable module category of a Ding-Chen ring $R$, by way of modules we call Gorenstein FP-pro-injective. These are modules that appear as a cycle module of a totally acyclic complex of FP-projective-injective modules. As a completely separate application of the new model category method, we show that all complete cotorsion pairs, even non-hereditary ones, lift to abelian models for the derived category of a ring.
