ABSTRACT
Representations of the bimodule Ext A 1 ( − , − ) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429187759/559656af-5888-4439-a5d2-08d7a38d7161/content/inq_chapter7_65_1.tif"/> and fibre sum functors both provide techniques for the investigation of module categories for finite-dimensional algebras. We clarify the relation between these two constructions.
