On the global dimension three endomorphism algebras of the minimal generator-cogenerator

Abstract: The main goal of this paper is to study the class of algebras for which the global dimension of the endomorphism ring of the generator-cogenerator, given by the sum of the projective and injective modules, is equal to three. We will refer to these algebras as representation-hereditary algebras. We show that these algebras are torsionless-finite, as defined by Ringel. These algebras do not necessarily have finite global dimension; however, when there is no non-zero morphism from an injective to a projective module, they have global dimension less than or equal to two, with some additional homological properties. By utilizing the general framework provided by the study of the representation dimension of an algebra, we present further homological consequences. In the case where these algebras are tame quasi-tilted algebras, we prove that they belong to certain classes of tilted algebras. Although not all tilted algebras are representation-hereditary, we provide sufficient conditions for them to be representation-hereditary.