A reduction theorem for τ-rigid modules

Eisele, F., Janssens, G. and Raedschelders, T. (2018) A reduction theorem for τ-rigid modules. Mathematische Zeitschrift, 290(3-4), pp. 1377-1413. (doi: 10.1007/s00209-018-2067-4)

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Abstract

We prove a theorem which gives a bijection between the support τ -tilting modules over a given finite-dimensional algebra A and the support τ -tilting modules over A / I, where I is the ideal generated by the intersection of the center of A and the radical of A. This bijection is both explicit and well-behaved. We give various corollaries of this, with a particular focus on blocks of group rings of finite groups. In particular we show that there are τ -tilting-finite wild blocks with more than one simple module. We then go on to classify all support τ -tilting modules for all algebras of dihedral, semidihedral and quaternion type, as defined by Erdmann, which include all tame blocks of group rings. Note that since these algebras are symmetric, this is the same as classifying all basic two-term tilting complexes, and it turns out that a tame block has at most 32 different basic two-term tilting complexes. We do this by using the aforementioned reduction theorem, which reduces the problem to ten different algebras only depending on the ground field k, all of which happen to be string algebras. To deal with these ten algebras we give a combinatorial classification of all τ -rigid modules over (not necessarily symmetric) string algebras.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Raedschelders, Mr Theo and Eisele, Dr Florian
Authors: Eisele, F., Janssens, G., and Raedschelders, T.
College/School:College of Science and Engineering > School of Mathematics and Statistics
College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Mathematische Zeitschrift
Publisher:Springer
ISSN:0025-5874
ISSN (Online):1432-1823
Published Online:05 June 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in Mathematische Zeitschrift 290(3-4): 1377-1413
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
3014430Reductions and Resolutions in representation theory and algebraic geometryTheo RaedscheldersEngineering and Physical Sciences Research Council (EPSRC)EP/R005214/1M&S - Mathematics