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1988, Journal of Algebra
AI
This article addresses crucial problems concerning the Gelfand-Kirillov (GK) dimension of algebras and modules, specifically when this dimension is an integer and under what conditions exactness holds in short exact sequences of modules. Significant results are obtained related to the conditions needed for integer GK-dimensions and exactness across various classes of algebras, with a detailed analysis of the behavior of filtrations under intersection with submodules and ideals. The study further explores the rationality of Poincare series for graded modules, advancing the understanding of GK-dimensions in non-commutative settings.
Mathematische Zeitschrift, 1981
2006
In this article, we introduce and study a generalization of the classical Krull dimension for a module R M. This is defined to be the length of the longest strong chain of prime submodules of M (defined later) and, denoted by Cl.K.dim(M). This notion is analogous to that of the usual classical Krull dimension of a ring. This dimension, Cl.K.dim(M) exists if and only if M has virtual acc on prime submodules; see Section 2. If R is a ring for which Cl.K.dim(R) exists, then for any left R-module M, Cl.K.dim(M) exists and is no larger than Cl.K.dim(R). Over any ring, all homogeneous semisimple modules and over a PI-ring (or an FBN-ring), all semisimple modules as well as, all Artinian modules with a prime submodule lie in the class of modules with classical Krull dimension zero. For a multiplication module over a commutative ring, the notion of classical Krull dimension and the usual prime dimension coincide. This yields that for a multiplication module M, Cl.K.dim(M) exists if and only if M has acc on prime submodules. As an application, we obtain a nice generalization of Cohen's Theorem for multiplication modules. Also, PI-rings whose nonzero modules have zero classical Krull dimension are characterized.
arXiv preprint arXiv:1206.3726, 2012
The structure of arbitrary associative commutative unital artinian algebras is well-known: they are finite products of associative commutative unital local algebras pg.351, Cor. 23.12]. In the semi-simple case, we have the Artin-Wedderburn Theorem which states that any semi-simple artinian algebra (which is assumed to be associative and unital but not necessarily commutative) is a direct product of matrix algebras over division rings pg.35, Par. 3.5]. Along these lines, we observe a simple classification of artinian algebras and their representations in Proposition 1.3.2 (hereby referred as the Classification Lemma) in terms of a category in which each object has a local artinian endomorphism algebra. This category is constructed using a fixed set of primitive (not necessarily central) idempotents in the underlying algebra. The Classification Lemma is a version of Freyd's Representation Theorem [4, Sect. 5.3]: from an artinian algebra A we create a category C A on finitely many objects, and then the category of A-modules can be realized as a category of functors which admit C A as their domain. This construction can also be thought as a higher dimensional analogue of the semi-trivial extensions of [10] for artinian algebras.
Glasgow Mathematical Journal, 2008
We prove some results on algebras, satisfying many generic relations. As an application we show that there are Golod–Shafarevich algebras which cannot be homomorphically mapped onto infinite dimensional algebras with finite Gelfand–Kirillov dimension. This answers a question of Zelmanov (Some open problems in the theory of infinite dimensional algebras, J. Korean Math. Soc. 44(5) 2007, 1185–1195).
Journal of Algebra, 2009
We introduce the notion of relative hereditary Artin algebras, as a generalization of algebras with representation dimension at most 3. We prove the following results. (1) The relative hereditariness of an Artin algebra is left-right symmetric and is inherited by endomorphism algebras of projective modules. (2) The finitistic dimensions of a relative hereditary algebra and its opposite algebra are finite. As a consequence, the finitistic projective dimension conjecture, the finitistic injective dimension conjecture, the Gorenstein symmetry conjecture, the Wakamatsu-tilting conjecture and the generalized Nakayama conjecture hold for relative hereditary Artin algebras and endomorphism algebras of projective modules over them (in particular, over algebras with representation dimension at most 3). We also show that the torsionless-finiteness of an Artin algebra is inherited by endomorphism algebras of projective modules, and consequently give a partial answer to the question if the representation dimension of the endomorphism algebra of any projective module over an Artin algebra A is bounded by the representation dimension of A.
Proceedings of the American Mathematical Society, 2005
We consider algebras over a field K presented by generators x 1 ,. .. , x n and subject to n 2 square-free relations of the form x i x j = x k x l with every monomial x i x j , i = j, appearing in one of the relations. It is shown that for n > 1 the Gelfand-Kirillov dimension of such an algebra is at least two if the algebra satisfies the so-called cyclic condition. It is known that this dimension is an integer not exceeding n. For n ≥ 4, we construct a family of examples of Gelfand-Kirillov dimension two. We prove that an algebra with the cyclic condition with generators x 1 ,. .. , x n has Gelfand-Kirillov dimension n if and only if it is of I-type, and this occurs if and only if the multiplicative submonoid generated by x 1 ,. .. , x n is cancellative.
Archiv der Mathematik, 1994
2005
We find a simple condition which implies finiteness of fini- tistic global dimension for artin algebras. As a consequence we obtain a short proof of the finitistic global dimension conjecture for radical cubed zero algebras. The same condition also holds for algebras of representa- tion dimension less then or equal to three. Hence the finitistic dimension conjecture holds in that
Journal of Algebra, 2008
Let R be a finite dimensional k-algebra over an algebraically closed field k and mod R be the category of all finitely generated left R-modules. For a given full subcategory X of mod R, we denote by pfd X the projective finitistic dimension of X. That is, pfd X := sup {pd X : X ∈ X and pd X < ∞}. It was conjectured by H. Bass in the 60's that the projective finitistic dimension pfd (R) := pfd (mod R) has to be finite. Since then, much work has been done toward the proof of this conjecture. Recently, K. Igusa and J. Todorov defined in [9] a function Ψ : mod R → N, which turned out to be useful to prove that pfd (R) is finite for some classes of algebras. In order to have a different approach to the finitistic dimension conjecture, we propose to consider a class of full subcategories of mod R instead of a class of algebras, namely to take the class of categories F (θ) of θ-filtered R-modules for all stratifying systems (θ, ≤) in mod R.
2003
Suppose that A is a semiprimary ring satisfying one of the two conditions: 1) its Yoneda ring is generated in finite degrees; 2) its Loewy length is less or equal than three. We prove that the global dimension of A is finite if, and only if, there is a m> 0 such that Ext n A(S, S) = 0, for all simple A-modules S and all n≥m In a recent paper, Skowronski, Smal ∅ and Zacharia ([8]) proved that a left Artinian ring A has finite global dimension if, and only if, every finitely generated indecomposable left A-module has either finite projective dimension or finite injective dimension. Then, they showed that one cannot replace ’indecomposable’ by ’simple ’ in that statement, by giving a counterexample of Loewy length 4. Finally they asked the following question: Question: Suppose A is a left Artinian ring such that, for each finitely (M, M) = 0 for n ≫ generated indecomposable left A-module M, one has Extn A 0 (i.e. there is a m = m(M)> 0 such that Extn A (M, M) = 0 for all n ≥ m). ...
Journal of Algebra, 2006
We find a bound for the Goldie dimension of hereditary modules in terms of the cardinality of the generating sets of their quasi-injective hulls. Several consequences are deduced. In particular, it is shown that every finitely generated hereditary module with countably generated quasi-injective hull is noetherian. It is also shown that every right hereditary ring with finitely generated injective hull is right artinian, thus answering a long standing open question posed by Dung, Gómez Pardo and Wisbauer.
Journal of Algebra, 2010
The category of all additive functors Mod(mod Λ) for a finite dimensional algebra Λ were shown to be left Noetherian if and only if Λ is of finite representation type by M. Auslander. Here we consider the category of all additive graded functors from the category of associated graded category of mod Λ to graded vectorspaces. This category decomposes into subcategories corresponding to the components of the Auslander-Reiten quiver. For a regular component we show that the corresponding graded functor category is left Noetherian if and only if the section of the component is extended Dynkin or infinite Dynkin.
2020
It is a well-known result of Auslander and Reiten that contravariant finiteness of the class P^fin_∞ (of finitely generated modules of finite projective dimension) over an Artin algebra is a sufficient condition for validity of finitistic dimension conjectures. Motivated by the fact that finitistic dimensions of an algebra can alternatively be computed by Gorenstein projective dimension, in this work we examine the Gorenstein counterpart of Auslander–Reiten condition, namely contravariant finiteness of the class GP^fin_∞ (of finitely generated modules of finite Gorenstein projective dimension), and its relation to validity of finitistic dimension conjectures. It is proved that contravariant finiteness of the class GP^fin_∞ implies validity of the second finitistic dimension conjecture over left artinian rings. In the more special setting of Artin algebras, however, it is proved that the Auslander–Reiten sufficient condition and its Gorenstein counterpart are virtually equivalent in ...
Proceedings of the Edinburgh Mathematical Society, 1999
We consider associative algebras filtered by the additive monoid ℕp. We prove that, under quite general conditions, the study of Gelfand-Kirillov dimension of modules over a multi-filtered algebra R can be reduced to the associated ℕp-graded algebra G(R). As a consequence, we show the exactness of the Gelfand-Kirillov dimension when the multi-filtration is finite-dimensional and G(R) is a finitely generated noetherian algebra. Our methods apply to examples like iterated Ore extensions with arbitrary derivations and “homothetic” automorphisms (e.g. quantum matrices, quantum Weyl algebras) and the quantum enveloping algebra of sl(v + 1)
2012
2010 Mathematics Subject Classification: 16R10, 16W55, 15A75.We survey some recent results on graded Gelfand-Kirillov dimension of PI-algebras over a field F of characteristic 0. In particular, we focus on verbally prime algebras with the grading inherited by that of Vasilovsky and upper triangular matrices, i.e., UTn(F), UTn(E) and UTa,b(E), where E is the infinite dimensional Grassmann algebra
2012
Abstract. We show that an artin algebra Λ having at most three radical layers of infinite projective dimension has finite finitistic dimension, generalizing the known result for algebras with vanishing radical cube. We also give an equivalence between the finiteness of fin.dim.Λ and the finiteness of a given class of Λ-modules of infinite projective dimension. 1. Introduction. Let Λ be an artin algebra, and consider mod Λ the class of finitely generated left Λ-modules. The finitistic dimension of Λ is then defined to be fin.dim. Λ = sup{pdM: M ∈ mod Λ and pdM < ∞}, where pd M denotes the projective dimension of M. It was conjectured by Bass in
"Representations of algebras and related topics"
Institutt for matematiske fag, NTNU NO-7491 Trondheim Norway [email protected] Dedicated to Professor Vlastimil Dlab on the occation of his sixtieth birthday.
2016
For an arbitrary countable field, we construct an associative algebra that is graded, generated by finitely many degree-1 elements, is Jacobson radical, is not nil, is prime, is not PI, and has Gelfand-Kirillov dimension two. This refutes a conjecture attributed to Goodearl.
In this article we obtain lower and upper bounds for global dimensions of a class of artinian algebras in terms of global dimensions of a finite subset of their artinian subalgebras. Finding these bounds for the global dimension of an artinian algebra $A$ is realized via an explicit algorithm we develop. This algorithm is based on a directed graph (not the Auslander-Reiten quiver) we construct, and it allows us to decide whether an artinian algebra has finite global dimension in good number of cases.
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