Graded change of ring

Abstract

We investigate scalar restriction, scalar extension, and scalar coextension functors for graded modules, including their interplay with coarsening  functors, graded tensor products, and graded Hom functors. This leads to several characterisations of epimorphisms of graded rings.

Key words: Graded module, coarsening, scalar restriction, scalar extension, scalar coextension, epimorphism of rings.