An element x of a Lie algebra L over the field F is extremal if [x, [x, L]] = Fx. Under minor assumptions, it is known that, for a simple Lie algebra L, the extremal geometry E(L) is a subspace of the projective geometry of L and either has no lines or is the root shadow space of an irreducible spherical building ∆. We prove that if ∆ is of simply-laced type, then L is a quotient of a Chevalley...

Rational vertex operator algebras, which play a fundamental role in rational conformal field theory (see [BPZ] and [MS]), single out an important class of vertex operator algebras. Most vertex operator algebras which have been studied so far are rational vertex operator algebras. Familiar examples include the moonshine module V ♮ ([B], [FLM], [D2]), the vertex operator algebras VL associated wi...

In this paper we study the algebra L(Σ) generated by links in the manifold Σ¬[0, 1] where Σ is an oriented surface. This algebra has a filtration and the associated graded algebra L Gr (Σ) is naturally a Poisson algebra. There is a Poisson algebra homomorphism from the algebra ch (Σ) of chord diagrams on Σ to L Gr (Σ). We show that multiplication in L (Σ) provides a geometric way to define a de...

Given an inductive limit group G = lim → Gβ , β ∈ Γ where each Gβ is locally compact, and a continuous two–cocycle ρ ∈ Z(G, T) , we construct a C*–algebra L for which the twisted discrete group algebra C∗ ρ (Gd) is imbedded in its multiplier algebra M(L) , and the representations of L are identified with the strong operator continuous ρ–representations of G . If any of these representations are...

In this paper, we investigate the relation between L-projections and conditional expectations on subalgebras of the Fourier Stieltjes algebra B(G), and we will show that compactness of G plays an important role in this relation.

In this article we work with the degenerate affine Hecke algebra Hl corresponding to the general linear group GLl over a local non-Archimedean field. This algebra was introduced by V.Drinfeld in [D], see also [L]. The complex associative algebra Hl is generated by the symmetric group algebra CSl and by the pairwise commuting elements x1 , . . . , xl with the cross relations for p = 1 , . . . , ...

In this paper we consider C0-group of unitary operators on a Hilbert C*-module E. In particular we show that if A?L(E) be a C*-algebra including K(E) and ?t a C0-group of *-automorphisms on A, such that there is x?E with =1 and ?t (?x,x) = ?x,x t?R, then there is a C0-group ut of unitaries in L(E) such that ?t(a) = ut a ut*.

An isomorphism is established between the plethystic Hopf algebra Pleth(Super[L]) and the algebra of vector symmetric functions. The Hall inner product of symmetric function theory is extended to the Hopf algebra Pleth(Super[L]).

We introduce 3-irreducible modules, even roots and odd roots for Leibniz algebras, produce a basis for a root space of a Leibniz algebra with a semisimple Lie factor, and classify finite dimensional simple Leibniz algebras with Lie factor sl2. In this paper, all vector spaces are vector spaces over an algebraically closed field k of characteristic 0. This paper consists of three sections. In Se...