Abelian Quasi-Ordered Groups

TL;DR

This paper explores the structure of quasi-ordered abelian groups, extending the theory of lattice-ordered groups by examining their fundamental properties and categorical relationships.

Contribution

It introduces a categorical framework for quasi-ordered abelian groups, showing they form a monadic category over set monomorphisms, generalizing existing theories.

Findings

Characterization of quasi-ordered abelian groups

Relationship to partially ordered and lattice-ordered groups

Category of quasi-ordered abelian groups is monadic over set monomorphisms

Abstract

Abelian groups having partial orderings compatible with their binary operations have long been studied in the literature. In particular, lattice-ordered abelian groups constitute a universal-algebraic variety, and thus form a category which is monadic over the category of sets. The current paper studies the more general case of quasi-ordered abelian groups, identifying some of their more fundamental properties and their relationships to partially ordered and lattice-ordered groups. We reinterpret the category of quasi-ordered abelian groups with order preserving morphisms by examining the interplay between the group and the set of all positive elements under the quasi-ordering. The main result shows that the category of quasi-ordered abelian groups is monadic over the category of set monomorphisms.