arXiv subjects

Ögmundur Eiriksson

Publications and source records attributed to Ögmundur Eiriksson.

2 recordsLinked to original sources

arXiv2018

Quiver-graded Richardson Orbits

In Lie theory, a dense orbit in the unipotent radical of a parabolic group under the adjoint action is called a Richardson orbit. We define a quiver-graded version of Richardson orbits generalising the classical definition in the case of the general linear group. In our setting a product of parabolic subgroups of general linear groups acts on a closed subvariety of the representation space of a quiver. Such dense orbits do not exist in general. We define a quasi-hereditary algebra called the nilpotent quiver algebra whose isomorphism classes of $Δ$-filtered modules correspond to orbits in our generalised setting. We translate the existence of a Richardson orbit into the existence of a rigid $Δ$-filtered module of a given dimension vector. We study an idempotent recollement of this algebra whose associated intermediate extension functor can be used to produce Richardson orbits in some situations. This can be explicitly calculated in examples. We also give examples where no Richardson orbit exists.

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arXiv2017

From Submodule Categories to the Stable Auslander Algebra

We construct two functors from the submodule category of a self-injective representation-finite algebra $Λ$ to the module category of the stable Auslander algebra of $Λ$. These functors factor through the module category of the Auslander algebra of $Λ$. Moreover they induce equivalences from the quotient categories of the submodule category modulo their respective kernels and said kernels have finitely many indecomposable objects up to isomorphism. Their construction uses a recollement of the module category of the Auslander algebra induced by an idempotent and this recollement determines a characteristic tilting and cotilting module. If $Λ$ is taken to be a Nakayama algebra, then said tilting and cotilting module is a characteristic tilting module of a quasi-hereditary structure on the Auslander algebra. We prove that the self-injective Nakayama algebras are the only algebras with this property.

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