1-quasi-hereditary algebras: Examples and invariant submodules of projectives

Abstract

In arXiv:1104.4441 it was shown that any 1-quasi-hereditary algebra affords a particular basis which is related to a given partial order on the set of simple modules. We show that the modules generated by these basis-elements are also modules over the endomorphism algebra of some projective indecomposable modules. In case the Ringel-dual of a 1-quasi-hereditary algebra is also 1-quasi-hereditary, we describe all local Delta-good submodules of projective indecomposable modules. We also consider several examples.