Primitive Elements and Automorphisms of Free Algebras of Schreier Varieties

In this article, we review results on primitive elements of free algebras of main types of Schreier varieties of algebras. A variety of linear algebras over a field is Schreier if any subalgebra of a free algebra of this variety is free in the same variety of algebras. A system of elements of a free algebra is primitive if it is a subset of some set of free generators of this algebra. We consider free nonassociative algebras, free commutative and anti-commutative nonassociative algebras, free Lie algebras and superalgebras, and free Lie p-algebras and p-superalgebras. We present matrix criteria for systems of elements of elements. Primitive elements distinguish automorphisms: endomorphisms sending primitive elements to primitive elements are automorphisms. We give a series of examples of almost primitive elements (an element of a free algebra is almost primitive if it is not a primitive element of the whole algebra, but it is a primitive element of any proper subalgebra which contains it). We also consider generic elements and Δ-primitive elements. Translated from Itogi Nauki i Tekhniki, Seriya Sovremennaya Matematika i Ee Prilozheniya. Tematicheskie Obzory. Vol. 74, Algebra-15, 2000.     

Trialitarian automorphisms of lie algebras

Over an algebraically closed field of characteristic zero simple Lie algebras admit outer automorphisms of order 3 if and only if they are of type D₄. Moreover, thereare two conjugacy classes of such automorphisms. Among orthogonal Lie algebras over arbitrary fields of characteristic zero, only orthogonal Lie algebras relative to quadratic norm forms of Cayley algebras admit outer automorphisms of order 3. We give a complete list of conjugacy classes of outer automorphisms of order 3 for orthogonal Lie algebras over arbitrary fields of characteristic zero. For the norm form of a given Cayley algebra, one class is associated with the Cayley algebra and the others with central simple algebras of degree 3 with involution of the second kind such that the cohomological invariant of the involution is the norm form.     

A survey on stability and rigidity results for Lie algebras

We give simple and unified proofs of the known stability and rigidity results for Lie algebras, Lie subalgebras and Lie algebra homomorphisms. Moreover, we investigate when a Lie algebra homomorphism is stable under all automorphisms of the codomain (including outer automorphisms).     

Finite gradings of special linear Lie algebras

In this paper, we study gradings of simple classical Lie algebras with arbitrary Abelian groups and the interconnection of such gradings and automorphism groups of Lie algebras. We give a complete classification of gradings of special linear Lie algebras that are specified by inner automorphisms in the case of an algebraically closed field of zero characteristic.     

无限秩仿射李代数的cartan子代数的共轭性

本文给出了无限秩仿射李代数的某种类型的Cartan子代数的定义,并证明了这种Cartan子代数在无限秩仿射李代数的某种类型的自同构下的共轭性.     

Conjugacy of Cartan subalgebras inn-Lie algebras

One of the most profound results in the theory of Lie algebras states that any two Cartan subalgebras of a finite-dimensional Lie algebra over an algebraically closed field of characteristic 0 are conjugate relative to the group of special automorphisms generated by the exponents of nilpotent inner derivations. Using some new ideas, we prove an analog of this statement for n-ary n-Lie algebras. Other interesting properties of Cartan algebras, which are known to be shared by Lie algebras, are carried over to n-Lie algebras.Translated fromAlgebra i Logika, Vol. 34, No. 4, pp. 405–419, July-August, 1995.     

Anosov Lie algebras and algebraic units in number fields

We study nilmanifolds admitting Anosov automorphisms by applying elementary properties of algebraic units in number fields to the associated Anosov Lie algebras. We identify obstructions to the existence of Anosov Lie algebras. The case of 13-dimensional Anosov Lie algebras is worked out as an illustration of the technique. Also, we recapture the following known results: (1) Every 7-dimensional Anosov nilmanifold is toral, and (2) every 8-dimensional Anosov Lie algebra with 3 or 5-dimensional derived algebra contains an abelian factor.     

Some General Results on Conformal Embeddings of Affine Vertex Operator Algebras

We give a general criterion for conformal embeddings of vertex operator algebras associated to affine Lie algebras at arbitrary levels. Using that criterion, we construct new conformal embeddings at admissible rational and negative integer levels. In particular, we construct all remaining conformal embeddings associated to automorphisms of Dynkin diagrams of simple Lie algebras. The semisimplicity of the corresponding decompositions is obtained by using the concept of fusion rules for vertex operator algebras.     

Isomorphism classes of finite dimensional connected Hopf algebras in positive characteristic

We classify all finite-dimensional connected Hopf algebras with large abelian primitive spaces. We show that they are Hopf algebra extensions of restricted enveloping algebras of certain restricted Lie algebras. For any abelian matched pair associated with these extensions, we construct a cohomology group, which classifies all the extensions up to equivalence. Moreover, we present a 1–1 correspondence between the isomorphism classes and a group quotient of the cohomology group deleting some exceptional points, where the group respects the automorphisms of the abelian matched pair and the exceptional points represent those restricted Lie algebra extensions.     

紧致黎曼4-对称空间的Cartan嵌入

本文首先给出齐性空间的Ｃａｒｔａｎ嵌入的概念,然后利用李群、李代数的自同构理论,决定了使其Ｃａｒｔａｎ嵌入是极小的那些紧致黎曼４-对称空间．     

Cartan automorphisms and Vogan superdiagrams

The real forms of complex semisimple Lie algebras are characterized by Cartan involutions and Vogan diagrams. We extend these notions to the Cartan automorphisms and Vogan superdiagrams, and show that they characterize the real forms of complex contragredient Lie superalgebras.     

Descent constructions for central extensions of infinite dimensional Lie algebras

We use Galois descent to construct central extensions of twisted forms of split simple Lie algebras over rings. These types of algebras arise naturally in the construction of Extended Affine Lie Algebras. The construction also gives information about the structure of the group of automorphisms of such algebras. A. Pianzola is supported by the NSERC Discovery Grant Program. The author also wishes to thank the Instituto Argentino de Matemática for their hospitality. D. Prelat is supported by a Research Grant from Universidad CAECE.     

On Anosov automorphisms of nilmanifolds

The only known examples of Anosov diffeomorphisms are hyperbolic automorphisms of infranilmanifolds, and the existence of such automorphisms is a really strong condition on the rational nilpotent Lie algebra determined by the lattice, so called an Anosov Lie algebra. We prove that n⊕?⊕n (s times, s≥2) has an Anosov rational form for any graded real nilpotent Lie algebra n having a rational form. We also obtain some obstructions for the types of nilpotent Lie algebras allowed, and use the fact that the eigenvalues of the automorphism are algebraic integers (even units) to show that the types (5,3) and (3,3,2) are not possible for Anosov Lie algebras.     

Automorphisms and primitive elements of free lie superalgebras

We consider images of primitive elements of free color Lie (p-)su per algebras under endomorphisms of these algebras Web prove that endomorphisms preserving primitivity of elements are automorphisms (Theorem 4). Note that for free groups this problem was discussed in [10], Problem 2a. At the same time we show that it is not true if we consider only images of linear combinations of elements from free generatig set (see Example, Theorem 5). We formulate some open questions. In Section 1 we give necessary definitions and collect preliminary results. In Section 2 we prove main theorems. The results of this article were presented at algebraic semi­nars of Moscow State University.     

On Minimal Permutation Representations of Classical Simple Groups

We describe minimal permutation representations, i.e., faithful permutation representations of least degree, of classical finite simple groups as groups of automorphisms of simple Lie algebras.     

Stabilizers of subspaces under similitudes of the Klein quadric,and automorphisms of Heisenberg algebras

We determine the groups of automorphisms and their orbits for nilpotent Lie algebras of class 2 and small dimension, over arbitrary fields (including the characteristic 2 case).     

Bases, filtrations and module decompositions of free Lie algebras

We use the technique known as elimination to devise some new bases of the free Lie algebra which (like classical Hall bases) consist of Lie products of left normed basic Lie monomials. Our bases yield direct decompositions of the homogeneous components of the free Lie algebra with direct summands that are particularly easy to describe: they are tensor products of metabelian Lie powers. They also give rise to new filtrations and decompositions of free Lie algebras as modules for groups of graded algebra automorphisms. In particular, we obtain some new decompositions for free Lie algebras and free restricted Lie algebras over fields of positive characteristic.     

限制李超代数的诱导模

In this paper we first prove the PBW theorem for reduced universal enveloping algebras of restricted Lie superalgebras. Then the notion of an induced module is introduced and the dimension formula of induced modules is established. Finally, using the results above, we obtain a property of induced modules pertaining to automorphisms of Lie superalgebras and isomorphisms of modules.     

Geometry of Higgs bundles over elliptic curves related to automorphisms of simple Lie algebras,Calogero–Moser systems,and KZB equations

We construct twisted Calogero–Moser systems with spins as Hitchin systems derived from the Higgs bundles over elliptic curves, where the transition operators are defined by arbitrary finite-order automorphisms of the underlying Lie algebras. We thus obtain a spin generalization of the twisted D’Hoker–Phong and Bordner–Corrigan–Sasaki–Takasaki systems. In addition, we construct the corresponding twisted classical dynamical r-matrices and the Knizhnik–Zamolodchikov–Bernard equations related to the automorphisms of Lie algebras.