Indecomposables live in all smaller lengths
Representation Theory
2015-03-13 v2
Abstract
Let be a finite-dimensional -algebra with algebraically closed. Bongartz has recently shown that the existence of an indecomposable -module of length implies that also indecomposable -modules of length exist. Using a slight modification of his arguments, we strengthen the assertion as follows: If there is an indecomposable module of length , then there is also an accessible one. Here, the accessible modules are defined inductively, as follows: First, the simple modules are accessible. Second, a module of length is accessible provided it is indecomposable and there is a submodule or a factor module of length which is accessible.
Cite
@article{arxiv.0912.5002,
title = {Indecomposables live in all smaller lengths},
author = {Claus Michael Ringel},
journal= {arXiv preprint arXiv:0912.5002},
year = {2015}
}