Lengths of endomorphism rings of finitely generated indecomposable modules over artin algebras

1998 ◽  
Vol 70 (3) ◽  
pp. 182-186
Author(s):  
Sverre O. Smal� ◽  
Stig Ven�s
Keyword(s):  
Finitely Generated ◽  
Endomorphism Rings ◽  
Indecomposable Modules ◽  
Artin Algebras

The Inductive Step of the Second Brauer-Thrall Conjecture

1980 ◽  
Vol 32 (2) ◽  
pp. 342-349 ◽  
Author(s):  
Sverre O. Smalø
Keyword(s):  
Representation Theory ◽  
Finitely Generated ◽  
Inductive Step ◽  
Artin Algebra ◽  
Indecomposable Modules ◽  
Infinite Type ◽  
Categorical Methods ◽  
Artin Algebras ◽  
Almost Split Sequences ◽  
Finitely Generated Modules

In this paper we are going to use a result of H. Harada and Y. Sai concerning composition of nonisomorphisms between indecomposable modules and the theory of almost split sequences introduced in the representation theory of Artin algebras by M. Auslander and I. Reiten to obtain the inductive step in the second Brauer-Thrall conjecture.Section 1 is devoted to giving the necessary background in the theory of almost split sequences.As an application we get the first Brauer-Thrall conjecture for Artin algebras. This conjecture says that there is no bound on the length of the finitely generated indecomposable modules over an Artin algebra of infinite type, i.e., an Artin algebra such that there are infinitely many nonisomorphic indecomposable finitely generated modules. This result was first proved by A. V. Roiter [8] and later in general for Artin rings by M. Auslander [2] using categorical methods.

Minimal representation-infinite artin algebras

1994 ◽  
Vol 116 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Andrzej Skowroński
Keyword(s):  
Jacobson Radical ◽  
Minimal Representation ◽  
Finitely Generated ◽  
Artin Algebra ◽  
Indecomposable Modules ◽  
Artin Ring ◽  
Artin Algebras ◽  
Infinite Power

Let A be an artin algebra over a commutative artin ring R, mod A be the category of finitely generated right A-modules, and rad∞ (modA) be the infinite power of the Jacobson radical rad(modA) of modA. Recall that A is said to be representation-finite if mod A admits only finitely many non-isomorphic indecomposable modules. It is known that A is representation-finite if and only if rad∞ (mod A) = 0. Moreover, from the validity of the First Brauer–Thrall Conjecture [26, 2] we know that A is representation-finite if and only if there is a common bound on the length of indecomposable modules in mod A.

scholarly journals Isomorphisms between endomorphism rings of projective modules

1993 ◽  
Vol 35 (3) ◽  
pp. 353-355 ◽  
Author(s):  
José Luis García ◽  
Juan Jacobo Simón
Keyword(s):  
Morita Equivalence ◽  
Projective Modules ◽  
Finitely Generated ◽  
Endomorphism Rings ◽  
Morita Equivalent ◽  
Free Modules

Let R and S be arbitrary rings, RM and SN countably generated free modules, and let φ:End(RM)→End(sN) be an isomorphism between the endomorphism rings of M and N. Camillo [3] showed in 1984 that these assumptions imply that R and S are Morita equivalent rings. Indeed, as Bolla pointed out in [2], in this case the isomorphism φ must be induced by some Morita equivalence between R and S. The same holds true if one assumes that RM and SN are, more generally, non-finitely generated free modules.

BAER ENDOMORPHISM RINGS AND ENVELOPES

2010 ◽  
Vol 09 (03) ◽  
pp. 365-381 ◽  
Author(s):  
LIXIN MAO
Keyword(s):  
Direct Summand ◽  
Left Ideal ◽  
Nonempty Subset ◽  
Finitely Generated ◽  
Endomorphism Rings ◽  
Baer Ring ◽  
Baer Rings ◽  
Left Annihilator

R is called a Baer ring if the left annihilator of every nonempty subset of R is a direct summand of RR. R is said to be a left AFG ring in case the left annihilator of every nonempty subset of R is a finitely generated left ideal. In this paper, we study Baer rings and AFG rings of endomorphisms of modules in terms of envelopes. Some known results are extended.

Modules Whose Endomorphism Rings Are (m, n)-Coherent

2019 ◽  
Vol 26 (02) ◽  
pp. 231-242
Author(s):  
Xiaoqiang Luo ◽  
Lixin Mao
Keyword(s):  
Left Ideal ◽  
Endomorphism Ring ◽  
Finitely Generated ◽  
Endomorphism Rings ◽  
Von Neumann ◽  
Von Neumann Regular ◽  
Coherent Ring ◽  
Left Annihilator

Let M be a right R-module with endomorphism ring S. We study the left (m, n)-coherence of S. It is shown that S is a left (m, n)-coherent ring if and only if the left annihilator [Formula: see text] is a finitely generated left ideal of Mn(S) for any M-m-generated submodule X of Mn if and only if every M-(n, m)-presented right R-module has an add M-preenvelope. As a consequence, we investigate when the endomorphism ring S is left coherent, left pseudo-coherent, left semihereditary or von Neumann regular.

scholarly journals EXPLICIT CONSTRUCTION OF COMPANION BASES

2015 ◽  
Vol 58 (2) ◽  
pp. 357-384
Author(s):  
MARK JAMES PARSONS
Keyword(s):  
Root System ◽  
Explicit Construction ◽  
Finitely Generated ◽  
Root Lattice ◽  
Indecomposable Modules ◽  
Tilted Algebra ◽  
Underlying Graph ◽  
Inner Products ◽  
Dynkin Quiver ◽  
Mutation Type

AbstractA companion basis for a quiver Γ mutation equivalent to a simply-laced Dynkin quiver is a subset of the associated root system which is a$\mathbb{Z}$-basis for the integral root lattice with the property that the non-zero inner products of pairs of its elements correspond to the edges in the underlying graph of Γ. It is known in typeA(and conjectured for all simply-laced Dynkin cases) that any companion basis can be used to compute the dimension vectors of the finitely generated indecomposable modules over the associated cluster-tilted algebra. Here, we present a procedure for explicitly constructing a companion basis for any quiver of mutation typeAorD.

Simple reflexive modules over Artin algebras

2019 ◽  
Vol 18 (10) ◽  
pp. 1950193
Author(s):  
René Marczinzik
Keyword(s):  
Simple Module ◽  
Positive Answer ◽  
Finitely Generated ◽  
Artin Algebra ◽  
Large Classes ◽  
Gorenstein Algebras ◽  
Artin Algebras ◽  
Reflexive Modules

Let [Formula: see text] be an Artin algebra. It is well known that [Formula: see text] is selfinjective if and only if every finitely generated [Formula: see text]-module is reflexive. In this paper, we pose and motivate the question whether an algebra [Formula: see text] is selfinjective if and only if every simple module is reflexive. We give a positive answer to this question for large classes of algebras which include for example all Gorenstein algebras and all QF-3 algebras.

scholarly journals On Quiver Grassmannians and Orbit Closures for Gen-Finite Modules

2021 ◽  
Author(s):  
Matthew Pressland ◽  
Julia Sauter
Keyword(s):  
Orbit Closure ◽  
Finite Dimensional Algebra ◽  
Tilting Module ◽  
Endomorphism Rings ◽  
Dimensional Algebra ◽  
Indecomposable Modules ◽  
Quiver Grassmannians ◽  
Finite Dimensional ◽  
Orbit Closures ◽  
Endomorphism Algebras

AbstractWe show that endomorphism rings of cogenerators in the module category of a finite-dimensional algebra A admit a canonical tilting module, whose tilted algebra B is related to A by a recollement. Let M be a gen-finite A-module, meaning there are only finitely many indecomposable modules generated by M. Using the canonical tilts of endomorphism algebras of suitable cogenerators associated to M, and the resulting recollements, we construct desingularisations of the orbit closure and quiver Grassmannians of M, thus generalising all results from previous work of Crawley-Boevey and the second author in 2017. We provide dual versions of the key results, in order to also treat cogen-finite modules.

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