On Frobenius (completed) orbit categories

TL;DR

This paper explores the structure of Frobenius orbit categories, establishing functorial relationships with Gorenstein-projective modules, and applies these findings to Nakajima categories and cluster algebras.

Contribution

It introduces a fully faithful functor from Frobenius orbit categories into Gorenstein-projective modules and provides conditions for these categories to be Krull-Schmidt Frobenius categories.

Findings

Established a functor from orbit categories to Gorenstein-projective modules.

Provided conditions for the orbit categories to be extension-closed.

Applied results to Nakajima categories and cluster algebra contexts.

Abstract

Let ${\mathcal E}$ be a Frobenius category, ${\mathcal P}$ its subcategory of projective objects and $F:{\mathcal E} \to {\mathcal E}$ an exact automorphism. We prove that there is a fully faithful functor from the orbit category ${\mathcal E}/F$ into $\operatorname{gpr}({\mathcal P}/F)$, the category of finitely-generated Gorenstein-projective modules over ${\mathcal P}/F$. We give sufficient conditions to ensure that the essential image of ${\mathcal E}/F$ is an extension-closed subcategory of $\operatorname{gpr}({\mathcal P}/F)$. If ${\mathcal E}$ is in addition Krull-Schmidt, we give sufficient conditions to ensure that the completed orbit category ${\mathcal E} \ \widehat{\!\! /} F$ is a Krull-Schmidt Frobenius category. Finally, we apply our results on completed orbit categories to the context of Nakajima categories associated to Dynkin quivers and sketch applications to cluster algebras.