Auslander's formula and correspondence for exact categories

TL;DR

This paper extends Auslander's correspondence to exact categories using admissibly finitely presented functors, revealing how properties of the category are reflected in these functor categories and establishing a bijection with exact structures.

Contribution

It introduces a new functor category for exact categories and generalizes Auslander's correspondence, connecting exact structures with resolving subcategories.

Findings

Established a version of Auslander's correspondence for exact categories.

Characterized properties of exact categories via functor categories.

Linked exact structures to resolving subcategories of module categories.

Abstract

The Auslander correspondence is a fundamental result in Auslander-Reiten theory. In this paper we introduce the category $\operatorname{mod_{\mathsf{adm}}}(\mathcal{E})$ of admissibly finitely presented functors and use it to give a version of Auslander correspondence for any exact category $\mathcal{E}$. An important ingredient in the proof is the localization theory of exact categories. We also investigate how properties of $\mathcal{E}$ are reflected in $\operatorname{mod_{\mathsf{adm}}}(\mathcal{E})$, for example being (weakly) idempotent complete or having enough projectives or injectives. Furthermore, we describe $\operatorname{mod_{\mathsf{adm}}}(\mathcal{E})$ as a subcategory of $\operatorname{mod}(\mathcal{E})$ when $\mathcal{E}$ is a resolving subcategory of an abelian category. This includes the category of Gorenstein projective modules and the category of maximal Cohen-Macaulay modules as special cases. Finally, we use $\operatorname{mod_{\mathsf{adm}}}(\mathcal{E})$ to give a bijection between exact structures on an idempotent complete additive category $\mathcal{C}$ and certain resolving subcategories of $\operatorname{mod}(\mathcal{C})$.