Let R be a connected selfinjective Artin algebra. We prove that any almost split sequence ending at an Omega-perfect R-module of finite complexity has at most four non-projective summands in a chosen decomposition of the middle term into indecomposable modules. Moreover, we show that a chosen decomposition into indecomposable modules of the middle term of an almost split sequence ending at an R-module of complexity 1 lying in a regular component of the Auslander-Reiten quiver has at most two summands. Furthermore, we prove that the regular component is of type ZA_{infinity} or ZA_{infinity}/<tau^n>. We use this to study modules with eventually constant and eventually periodic Betti numbers.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:ntnu-12937 |
| Date | January 2011 |
| Creators | Toft, Tea |
| Publisher | Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, Institutt for matematiske fag |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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