On Artinian generalized local cohomology modules

Let R be a commutative Noetherian ring with non-zero identity and a be a maximal ideal of R. An R-module M is called minimax if there is a finitely generated submodule N of M such that M/N is Artinian. Over a Gorenstein local ring R of finite Krull dimension, we proved that the Socle of H _a ⁿ (R) is a minimax R-module for each n ≥ 0.     

A Cohen-type theorem for Artinian modules

We show that a finitely embedded module M over a commutative ring R is Artinian if the factor module M/(0 :_M P) is finitely embedded for every prime ideal P of R. Received: 10 June 2005     

Artinian level modules and cancellable sequences

In order to use dualization to study Hilbert functions of artinian level algebras we extend the notion of level sequences and cancellable sequences, introduced by Geramita and Lorenzini, to include Hilbert functions of certain artinian modules. As in the case of algebras a level sequence is cancellable, but now by dualization its reverse is also cancellable which gives a new condition on level sequences. We also give a characterization of the cancellable sequences involving Macaulay representations.     

On the Hartshorne-Speiser-Lyubeznik theorem about Artinian modules with a Frobenius action

Let be a commutative Noetherian local ring of prime characteristic. The purpose of this paper is to provide a short proof of G. Lyubeznik's extension of a result of R. Hartshorne and R. Speiser about a module over the skew polynomial ring (associated to and the Frobenius homomorphism , in the indeterminate ) that is both -torsion and Artinian over .

     

Artinian level modules of embedding dimension two

We prove that a sequence of positive integers (h₀,h₁,…,h_c) is the Hilbert function of an artinian level module of embedding dimension two if and only if h_i−1−2h_i+h_i+1≤0 for all 0≤i≤c, where we assume that h₋₁=h_c+1=0. This generalizes a result already known for artinian level algebras. We provide two proofs, one using a deformation argument, the other a construction with monomial ideals. We also discuss liftings of artinian modules to modules of dimension one.     

Loewy and Artinian modules over commutative rings

Sunto Si dimostra che se M è un modulo Artiniano con zoccolo semplice su un anello commutativo R, allora End_R(M) è commutativo locale Noetheriano completo e che M, come End_R (M)-modulo, è l'inviluppo iniettivo dell'unico End_R(M)-modulo semplice. Si dimostra anche che ogni modulo di Loewy con invarianti di Loewy finiti è Artiniano e si siudia la successione degli invarianti di Loewy di un tale modulo.     

On the character of certain tilting modules

Let G be a semisimple group over an algebraically closed field of characteristic p > 0. We give a (partly conjectural) closed formula for the character of many indecomposable tilting rational G-modules assuming that p is large.     

On supplementation and generalized projective modules

Discrete (quasi) modules form an important class in module theory, they are studied extensively by many authors. The decomposition theorem for quasidiscrete modules plays an important rule in the better understanding of such modules. In fact, every quasidiscrete module is a direct sum of hollow submodules. Here we introduce some new concepts (weak quasidiscrete, and S ₁- and S ₂-supplemented modules) which generalize the concept of quasidiscrete module. We show that some of the properties of quasidiscrete modules still hold in the class of weak quasidiscrete modules. We also obtain some properties of weak quasidiscrete modules, which are similar to the properties known for quasidiscrete modules. We introduce the concept of generalized relative projectivity (relative S-projectivemodules), and use it to characterize direct sums of hollowmodules. In fact, relative S-projectivity is an essential condition for direct sums of hollow modules to be weak quasidiscrete modules.     

Direct decompositions of Artinian modules over hypercyclic groups

Let G be a hypercyclic group and A be an Artianian G-module. A class of simple G-modules is defined and it is proved that there exists a direct decomposition A=C B, where C is a G-submodule, each G-composition factor of which belongs to the class , and B is a G-submodule that does not have G-composition factors belonging to .Deceased.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, Nos. 7 and 8, pp. 930–934, July–August, 1991.     

The central simple modules of Artinian Gorenstein algebras

Let A be a standard graded Artinian K-algebra, with char K=0. We prove the following.

1.

A has the Weak Lefschetz Property (resp. Strong Lefschetz Property) if and only if has the Weak Lefschetz Property (resp. Strong Lefschetz Property) for some linear form z of A.

2.

If A is Gorenstein, then A has the Strong Lefschetz Property if and only if there exists a linear form z of A such that all central simple modules of (A,z) have the Strong Lefschetz Property.

As an application of these theorems, we give some new classes of Artinian complete intersections with the Strong Lefschetz Property.     

On certain generalized matrix norms

Two methods of generating classes of generalized matrix norms are presented. Particular norms obtained in this manner are investigated in some detail.     

Tensor products of certain modules for the generalized cartan matrix lie algebra

The outer multiplicites of tensor product decompositions are computed for the smallest Euclidean Kac-Moody Lie algebra when one of the tensor factors is a fundamental module or the p-module. Some combinatorial identities are obtained.     

Artinian cofinite modules over complete Noetherian local rings

Let (R, m) be a complete Noetherian local ring, I an ideal of R and M a nonzero Artinian R-module. In this paper it is shown that if p is a prime ideal of R such that dim R/p = 1 and (0:M p) is not finitely generated and for each i ? 2 the R-module Ext _R ⁱ (M,R/p) is of finite length, then the R-module Ext _R ¹ (M, R/p) is not of finite length. Using this result, it is shown that for all finitely generated R-modules N with Supp(N) ? V (I) and for all integers i ? 0, the R-modules Ext _R ⁱ (N,M) are of finite length, if and only if, for all finitely generated R-modules N with Supp(N) ? V (I) and for all integers i ? 0, the R-modules Ext _R ⁱ (M,N) are of finite length.     

On Buchsbaum type modules and the annihilator of certain local cohomology modules

We consider the annihilator of certain local cohomology modules. Moreover, some results on vanishing of these modules will be considered.     

On unitarizable modules over generalized Virasoro algebras

We classify unitarizable modules with highest weight and unitarizable modules of an intermediate series over generalized Virasoro algebras. Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 50, No. 9, pp. 1278–1280, September, 1998.     

On multiplicities of simple subquotients in generalized Verma modules

We reduce the problem on multiplicities of simple subquotients in an -stratified generalized Verma module to the analogous problem for classical Verma modules.     

On certain generalized incomplete gamma functions

Recently, Chaudhry and Zubair have introduced a generalized incomplete gamma function Γ(v,x;z) which reduces to the incomplete gamma function Γ(v,x) when its variable z vanishes. We show that Γ(v,x;z) may be written essentially as a single Kampé de Fériet function which in turn may be expressed as a linear combination of two incomplete Weber integrals. Then by using properties of the latter integrals we deduce additional representations for Γ(v,x;z). In particular, we show that Γ(v,x;z) is essentially completely determined by a finite number of modified Bessel functions for all v ≠ 0 provided we know the values of the two incomplete Weber integrals when 0 < Re v ⩽ 1. When v = 0 we derive connections between the generalized incomplete gamma function and incomplete Lipschitz-Hankel integrals, and indicate that there exist connections with other special functions.     

On generalized derivations satisfying certain identities

Let R be a prime ring with char R ≠ 2 and let d be a generalized derivation on R. We study the generalized derivation d satisfying any of the following identities: