ON THE VARIATIONS OF G_2

In [1], Shen Guangyu constructed several classes of new simple Lie algebras of characteristic 2, which are called the variations of G2. In this paper, the authors investigate their derivation algebras. It is shown that G2 and its variations all possess unique nondegenerate associative forms. The authors also find some nonsingular derivations of ViG for i = 3,4, 5, 6, and thereby construct some left-symmetric structures on Vi G for i = 3,4,5,6. Some errors about the variations of sl(3, F) in [1] are corrected.     

On a Remarkable Class of Left-symmetric Algebras and its Relationship with the Class of Novikov Algebras

We discuss locally simply transitive affine actions of Lie groups G on finite-dimensional vector spaces such that the commutator subgroup [G, G] is acting by translations. In other words, we consider left-symmetric algebras satisfying the identity [x, y]·z = 0. We derive some basic characterizations of such left-symmetric algebras, and we highlight their relationships with the so-called Novikov algebras and derivation algebras.     

On Spectral Integral Variations of Graphs

Let G be a general graph. The spectrum S ( G ) of G is defined to be the spectrum of its Laplacian matrix. Let G + e be the graph obtained from G by adding an edge or a loop e . We study in this paper when the spectral variation between G and G + e is integral and obtain some equivalent conditions, through which a new Laplacian integral graph can be constructed from a known Laplacian integral graph by adding an edge.     

On Spectral Integral Variations of Graphs

Let G be a general graph. The spectrum S ( G ) of G is defined to be the spectrum of its Laplacian matrix. Let G + e be the graph obtained from G by adding an edge or a loop e . We study in this paper when the spectral variation between G and G + e is integral and obtain some equivalent conditions, through which a new Laplacian integral graph can be constructed from a known Laplacian integral graph by adding an edge.     

On the Centralizers of Derivations with Engel Conditions

Let R be a noncommutative prime ring and d, δ two nonzero derivations of R. If δ([d(x), x] _n ) = 0 for all x ∈ R, then char R = 2, d ² = 0, and δ = αd, where α is in the extended centroid of R. As an application, if char R ≠ 2, then the centralizer of the set {[d(x), x] _n  | x ∈ R} in R coincides with the center of R.     

Observations about the Lie algebra g2⊂so(7), associative 3-planes,and so(4) subalgebras

We make several observations relating the Lie algebra ${\mathfrak{g}}_2?\mathfrak{so}\left(7\right)$, associative 3-planes, and $\mathfrak{so}\left(4\right)$ subalgebras. Some are likely well-known but not easy to find in the literature, while other results are new. We show that an element $X\in {\mathfrak{g}}_2$ cannot have rank 2, and if it has rank 4 then its kernel is an associative subspace. We prove a canonical form theorem for elements of ${\mathfrak{g}}_2$. Given an associative 3-plane $P$ in ${\mathbb{R}}^7$, we construct a Lie subalgebra $\Theta \left(P\right)$ of $\mathfrak{so}\left(7\right)={\Lambda }^2\left({\mathbb{R}}^7\right)$ that is isomorphic to $\mathfrak{so}\left(4\right)$. This $\mathfrak{so}\left(4\right)$ subalgebra differs from other known constructions of $\mathfrak{so}\left(4\right)$ subalgebras of $\mathfrak{so}\left(7\right)$ determined by an associative 3-plane. These are results of an NSERC undergraduate research project. The paper is written so as to be accessible to a wide audience.     

On the Ideals of a Lie Ring of Derivations

Let R be a commutative ring, and D a Lie subring and an R-submodule of Der(R) such that R is D-semiprime (or D-prime). We investigate the structure of the ideals of D as Lie rings. As a consequence, we give a necessary and sufficient condition for the ideals of D to be semiprime (or prime, respectively) Lie rings.     

On minimum number of generators for some derivation modules

In this paper we study the generators of the module of derivations of certain rings and obtain bounds on their minimum number of generators. We will also study minimum number of generators of divisorial ideals of two dimensional rings of invariants, in particular the canonical modules of these rings.     

Classification of 2-Step Nilpotent Lie Algebras of Dimension 8 with 2-Dimensional Center

In this article, by choosing appropriate basis, we give a complete classification of 2-step nilpotent Lie algebras of dimension 8 with 2-dimensional center.     

Derivation Algebras and 2-Cocycles of the Algebras of q-Differential Operators

Abstract

In the paper, the deriviation algebras of the associative algebras of the one-variable (resp. multivariable) q-differential operators and of their corresponding Lie algebras are determined. The completeness of the derivation algebras of the algebras of q-differential operators is also discussed. Finally, we calculate H ²(𝒟 _q (n)^?, C) for n ≥ 1, as well as H ²(g l _n (𝒟 _q ), C) under the assumption that q is transcendental over the rational numbers field Q.     

On the product of two generalized derivations

Two elements and in a ring determine a generalized derivation on by setting for any in . We characterize when the product is a generalized derivation in the cases when the ring is the algebra of all bounded operators on a Banach space , and when is a -algebra . We use these characterizations to compute the commutant of the range of .

     

Spectral Integral Variations of Degree Maximal Graphs

The concept of the spectral integral variation was introduced by Fan [Fan Yizheng (2002). On spectral integral variations of graphs. Linear and Multilinear Algebra , 50 , 133-142] to study the general graphs with all changed eigenvalues moving up by integers when an edge is added. Here we consider the spectral integral variations of maximal graphs G , and successfully give an equivalent condition for the spectral integral variation of G occurring in two places by adding an edge e . We also characterize whether the graph G + e is maximal so that an explicit interpretation of the above condition is obtained, where G + e denotes the graph obtained from G by adding an edge e .     

Spectral Integral Variations of Degree Maximal Graphs

The concept of the spectral integral variation was introduced by Fan [Fan Yizheng (2002). On spectral integral variations of graphs. Linear and Multilinear Algebra , 50 , 133-142] to study the general graphs with all changed eigenvalues moving up by integers when an edge is added. Here we consider the spectral integral variations of maximal graphs G , and successfully give an equivalent condition for the spectral integral variation of G occurring in two places by adding an edge e . We also characterize whether the graph G + e is maximal so that an explicit interpretation of the above condition is obtained, where G + e denotes the graph obtained from G by adding an edge e .     

On Composition series relative to a module

ABSTRACT

A commutative algebra with the identity (a * b) * (c * d) ? (a * d) * (c * b) = (a, b, c) * d ? (a, d, c) * b is called Novikov–Jordan. Example: K[x] under multiplication a * b = ?(ab) is Novikov–Jordan. A special identity for Novikov–Jordan algebras of degree 5 is constructed. Free Novikov–Jordan algebras with q generators are exceptional for any q ≥ 1.

     

Unitary units in modular group algebras of 2-groups

We study the unitary subgroupV _?(F₂ G) in the group algebras F₂ Gof 2-groups of maximal class over the field F₂of two elements. We show that there does not exist a normal complement to Gin V _?(F₂ G) if and only if Gis the dihedral group of order 2ⁿ(n≥ 5) or the semidihedral group of order 2ⁿ(n≥5). We also describe V _?(F₂ G) when the subgroup Ghas order 8 and 16 and in this case there exist a normal complement of Gin V _?(F₂ G).     

Refinement of Ado's Theorem in Low Dimensions and Application in Affine Geometry

In this article, we construct a faithful representation with the lowest dimension for every complex Lie algebra in dimension ≤ 4. In particular, in our construction, in the case that the faithful representation has the same dimension of the Lie algebra, it can induce an étale affine representation with base zero which has a natural and simple form and gives a compatible left-symmetric algebra on the Lie algebra. Such affine representations do not contain any nontrivial one-parameter subgroups of translation.     

On Derivations of the Ternary Malcev Algebra M 8

Derivations of the simple ternary Malcev algebra M ₈ and its algebra of multiplications are described.