The spectrum of Grothendieck monoid: classifying Serre subcategories and reconstruction theorem

TL;DR

This paper introduces a classification framework for Serre subcategories of exact categories using the Grothendieck monoid, enabling reconstruction of scheme topology and providing new insights into algebraic and geometric structures.

Contribution

It establishes bijections between Serre subcategories, faces, and the monoid spectrum of the Grothendieck monoid, and applies these to classify subcategories and recover scheme topology.

Findings

Classifies Serre subcategories via Grothendieck monoid faces.

Reconstructs scheme topology from Grothendieck monoid.

Determines the Grothendieck monoid for coherent sheaves on curves.

Abstract

The Grothendieck monoid of an exact category is a monoid version of the Grothendieck group. We use it to classify Serre subcategories of an exact category and to reconstruct the topology of a noetherian scheme. We first construct bijections between (i) the set of Serre subcategories of an exact category, (ii) the set of faces of its Grothendieck monoid, and (iii) the monoid spectrum of its Grothendieck monoid. By using (ii), we classify Serre subcategories of exact categories related to a finite dimensional algebra and a smooth projective curve. In particular, we determine the Grothendieck monoid of the category of coherent sheaves on a smooth projective curve. By using (iii), we introduce a topology on the set of Serre subcategories. As a consequence, we recover the topology of a noetherian scheme from the Grothendieck monoid.