scholarly journals JACOBSON RADICAL ALGEBRAS WITH QUADRATIC GROWTH

2013 ◽  
Vol 55 (A) ◽  
pp. 135-147 ◽  
Author(s):  
AGATA SMOKTUNOWICZ ◽  
ALEXANDER A. YOUNG
Keyword(s):  
Jacobson Radical ◽  
Quadratic Growth ◽  
Closed Field ◽  
Finitely Generated ◽  
Algebraically Closed Field ◽  
Infinite Dimensional

AbstractWe show that over every countable algebraically closed field $\mathbb{K}$ there exists a finitely generated $\mathbb{K}$-algebra that is Jacobson radical, infinite-dimensional, generated by two elements, graded and has quadratic growth. We also propose a way of constructing examples of algebras with quadratic growth that satisfy special types of relations.

Ideals with Trivial Conormal Bundle

1980 ◽  
Vol 32 (1) ◽  
pp. 210-218 ◽  
Author(s):  
A. V. Geramita ◽  
C. A. Weibel
Keyword(s):  
Polynomial Ring ◽  
Maximal Ideal ◽  
Noetherian Ring ◽  
Question Answering ◽  
General Theorem ◽  
Closed Field ◽  
Natural Question ◽  
Finitely Generated ◽  
Algebraically Closed Field ◽  
Conormal Bundle

Throughout this paper all rings considered will be commutative, noetherian with identity. If R is such a ring and M is a finitely generated R-module, we shall use v(M) to denote that non-negative integer with the property that M can be generated by v(M) elements but not by fewer.Since every ideal in a noetherian ring is finitely generated, it is a natural question to ask what v(I) is for a given ideal I. Hilbert's Nullstellensatz may be viewed as the first general theorem dealing with this question, answering it when I is a maximal ideal in a polynomial ring over an algebraically closed field.More recently, it has been noticed that the properties of an R-ideal I are intertwined with those of the R-module I/I2.

scholarly journals Generating Adjoint Groups

2019 ◽  
Vol 62 (3) ◽  
pp. 733-738 ◽  
Author(s):  
Be'eri Greenfeld
Keyword(s):  
Open Problem ◽  
Jacobson Radical ◽  
The Other ◽  
Adjoint Group ◽  
Finitely Generated ◽  
Infinite Dimensional ◽  
Other Hand ◽  
Nil Ring

AbstractWe prove two approximations of the open problem of whether the adjoint group of a non-nilpotent nil ring can be finitely generated. We show that the adjoint group of a non-nilpotent Jacobson radical cannot be boundedly generated and, on the other hand, construct a finitely generated, infinite-dimensional nil algebra whose adjoint group is generated by elements of bounded torsion.

Constructing ω-stable structures: rank 2 fields

2000 ◽  
Vol 65 (1) ◽  
pp. 371-391 ◽  
Author(s):  
John T. Baldwin ◽  
Kitty Holland
Keyword(s):  
General Framework ◽  
Saturated Model ◽  
Closed Field ◽  
Morley Rank ◽  
Natural Numbers ◽  
Finitely Generated ◽  
Algebraically Closed Field ◽  
Fast Growing ◽  
Rank 2 ◽  
Stable Structures

AbstractWe provide a general framework for studying the expansion of strongly minimal sets by adding additional relations in the style of Hrushovski. We introduce a notion of separation of quantifiers which is a condition on the class of expansions of finitely generated models for the expanded theory to have a countable ω-saturated model. We apply these results to construct for each sufficiently fast growing finite-to-one function μ from ‘primitive extensions’ to the natural numbers a theory Tμ of an expansion of an algebraically closed field which has Morley rank 2. Finally, we show that if μ is not finite-to-one the theory may not be ω-stable.

On the complement of a nef and big divisor on an algebraic variety

1996 ◽  
Vol 120 (3) ◽  
pp. 411-422 ◽  
Author(s):  
Francesco Russo
Keyword(s):  
Algebraic Variety ◽  
Cartier Divisor ◽  
Ample Divisor ◽  
Closed Field ◽  
Finitely Generated ◽  
Complete Variety ◽  
Algebraically Closed Field

Let X be an algebraic (complete) variety over a fixed algebraically closed field k. To every Cartier divisor D on X, we can associate the graded k-algebra . As is known, for a semi-ample divisor D, R(X, D) is a finitely generated k-algebra (see [21] or [9]), while this property is no longer true for arbitrary nef and big divisors (see [21]).

scholarly journals A CRITERION FOR THE JACOBSON SEMISIMPLICITY OF THE GREEN RING OF A FINITE TENSOR CATEGORY

2017 ◽  
Vol 60 (1) ◽  
pp. 253-272 ◽  
Author(s):  
ZHIHUA WANG ◽  
LIBIN LI ◽  
YINHUO ZHANG
Keyword(s):  
Cyclic Group ◽  
Jacobson Radical ◽  
Tensor Category ◽  
Closed Field ◽  
Algebraically Closed Field ◽  
Green Ring ◽  
Isomorphism Classes

AbstractThis paper deals with the Green ring $\mathcal{G}(\mathcal{C})$ of a finite tensor category $\mathcal{C}$ with finitely many isomorphism classes of indecomposable objects over an algebraically closed field. The first part of this paper deals with the question of when the Green ring $\mathcal{G}(\mathcal{C})$, or the Green algebra $\mathcal{G}(\mathcal{C})\otimes_{\mathbb {Z}}$K over a field K, is Jacobson semisimple (namely, has zero Jacobson radical). It turns out that $\mathcal{G}(\mathcal{C})\otimes_{\mathbb {Z}}$K is Jacobson semisimple if and only if the Casimir number of $\mathcal{C}$ is not zero in K. For the Green ring $\mathcal{G}(\mathcal{C})$ itself, $\mathcal{G}(\mathcal{C})$ is Jacobson semisimple if and only if the Casimir number of $\mathcal{C}$ is not zero. The second part of this paper focuses on the case where $\mathcal{C}=\text{Rep}(\mathbb {k}G)$ for a cyclic group G of order p over a field $\mathbb {k}$ of characteristic p. In this case, the Casimir number of $\mathcal{C}$ is computable and is shown to be 2p2. This leads to a complete description of the Jacobson radical of the Green algebra $\mathcal{G}(\mathcal{C})\otimes_{\mathbb {Z}}$K over any field K.

scholarly journals On Some Infinite Dimensional Representations of Semi-Simple Lie Algebras

1965 ◽  
Vol 25 ◽  
pp. 211-220 ◽  
Author(s):  
Hiroshi Kimura
Keyword(s):  
Tensor Product ◽  
Lie Algebra ◽  
Lie Algebras ◽  
Irreducible Representations ◽  
Closed Field ◽  
Algebraically Closed Field ◽  
Infinite Dimensional ◽  
Complete Reducibility ◽  
Finite Dimensional

Let g be a semi-simple Lie algebra over an algebraically closed field K of characteristic 0. For finite dimensional representations of g, the following important results are known; 1) H1(g, V) = 0 for any finite dimensional g space V. This is equivalent to the complete reducibility of all the finite dimensional representations,2) Determination of all irreducible representations in connection with their highest weights.3) Weyl’s formula for the character of irreducible representations [9].4) Kostant’s formula for the multiplicity of weights of irreducible representations [6],5) The law of the decomposition of the tensor product of two irreducible representations [1].

scholarly journals GK DIMENSION AND LOCALLY NILPOTENT SKEW DERIVATIONS

2014 ◽  
Vol 57 (3) ◽  
pp. 555-567
Author(s):  
JEFFREY BERGEN ◽  
PIOTR GRZESZCZUK
Keyword(s):  
Closed Field ◽  
Finitely Generated ◽  
Natural Conditions ◽  
Skew Derivation ◽  
Algebraically Closed Field ◽  
Locally Nilpotent ◽  
Gk Dimension ◽  
Kirillov Dimension

AbstractLet A be a domain over an algebraically closed field with Gelfand–Kirillov dimension in the interval [2,3). We prove that if A has two locally nilpotent skew derivations satisfying some natural conditions, then A must be one of five algebras. All five algebras are Noetherian, finitely generated, and have Gelfand–Kirillov dimension equal to 2. We also obtain some results comparing the Gelfand–Kirillov dimension of an algebra to its subring of invariants under a locally nilpotent skew derivation.

scholarly journals Rings of differential operators on toric varieties

1994 ◽  
Vol 37 (1) ◽  
pp. 143-160 ◽  
Author(s):  
A. G. Jones
Keyword(s):  
Line Bundle ◽  
Toric Variety ◽  
Characteristic Zero ◽  
Differential Operators ◽  
Toric Varieties ◽  
Closed Field ◽  
Finitely Generated ◽  
Algebraically Closed Field ◽  
Finite Dimensional ◽  
Rings Of Differential Operators

Let be a finite dimensional toric variety over an algebraically closed field of characteristic zero, k. Let be the sheaf of differential operators on . We show that the ring of global sections, is a finitely generated Noetherian k-algebra and that its generators can be explicitly found. We prove a similar result for the sheaf of differential operators with coefficients in a line bundle.

On the Semisimplicity of Modular Group Algebras. II

1969 ◽  
Vol 21 ◽  
pp. 1137-1145 ◽  
Author(s):  
D. S. Passman
Keyword(s):  
Jacobson Radical ◽  
Modular Group ◽  
Discrete Group ◽  
Closed Field ◽  
Characteristic P ◽  
Metabelian Groups ◽  
Algebraically Closed Field ◽  
Normal Abelian Subgroup ◽  
Abelian Subgroups ◽  
Quotient Groups

Let G be a discrete group, let Kbe an algebraically closed field of characteristic p > 0 and let KGdenote the group algebra of Gover K.In a previous paper (2) I studied the Jacobson radical JKGof KGfor groups Gwith big abelian subgroups or quotient groups. It is therefore natural to next consider metabelian groups, and I do this here. The main result is as follows.THEOREM 1. Let K be an algebraically closed field of characteristic p and let a group G have a normal abelian subgroup A with G/A abelian. Then JKG ≠ {0} if and only if G has an element g of order p such that the A-conjugacy class gA is finite and such that the group is periodic.Note that since and G/Ais abelian, we do in fact have .

scholarly journals Unit Equations on Quaternions

2020 ◽  
Vol 71 (4) ◽  
pp. 1521-1534
Author(s):  
Yifeng Huang
Keyword(s):  
Classical Result ◽  
Quaternion Algebra ◽  
Multiplicative Group ◽  
Closed Field ◽  
Finitely Generated ◽  
Algebraically Closed Field ◽  
Forward Orbit ◽  
Unit Equations

Abstract A classical result about unit equations says that if Γ1 and Γ2 are finitely generated subgroups of ${\mathbb C}^\times$, then the equation x + y = 1 has only finitely many solutions with x ∈ Γ1 and y ∈ Γ2. We study a non-commutative analogue of the result, where $\Gamma_1,\Gamma_2$ are finitely generated subsemigroups of the multiplicative group of a quaternion algebra. We prove an analogous conclusion when both semigroups are generated by algebraic quaternions with norms greater than 1 and one of the semigroups is commutative. As an application in dynamics, we prove that if f and g are endomorphisms of a curve C of genus 1 over an algebraically closed field k, and deg( f), deg(g)≥ 2, then f and g have a common iterate if and only if some forward orbit of f on C(k) has infinite intersection with an orbit of g.

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