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The induction scheme used in Roiter's proof of the first Brauer-Thrall conjecture prompted Gabriel to introduce an invariant, known as the Gabriel-Roiter measure. The usefulness of the Gabriel-Roiter measure is not limited to the first Brauer-Thrall conjecture: Ringel has used it to give new proofs of results established by himself, Auslander and Tachikawa in the 70's. It turns out that the Gabriel-Roiter measure can also be used to provide an alternative proof of the finiteness of the representation dimension for Artin algebras, a result originally shown by Iyama in 2002. The concept of Gabriel-Roiter measure can be extended to abelian length categories and every such category has multiple Gabriel-Roiter measures. The aim of this talk is to clarify the following refined version of Iyama's theorem: given any object X and any Gabriel-Roiter measure m in an abelian length category, there exists an object X' which depends on X and m, such that the endomorphism ring of the direct sum of X with X' is quasihereditary, and hence has finite global dimension.

Date and Venue

Start Date
Venue
Room FC1 030, Mathematics building, FCUP

Speaker

Teresa Conde

Speaker's Institution

Universität Stuttgart

Area

Algebra, Combinatorics and Number Theory

Financiamento