Graded change of ring

Abstract

We investigate scalar restriction, scalar extension, and scalar coexten- sion functors for graded modules, including their interplay with coarsening functors, graded tensor products, and graded Hom functors. This leads to several character- isations of epimorphisms of graded rings.

Mathematics Subject Classification (2010):

• Primary: 16W50
• Secondary: 13A02

Key words:

• Graded module
• coarsening
• scalar restriction
• scalar extension
• scalar coex- tension
• epimorphism of rings