An important theorem in the theory of infinite dimensional Lie algebras states that any affine Kac-Moody algebra can be realized (that is to say constructed explicitly) using loop algebras. In this paper, we consider the corresponding problem for a class of Lie algebras called extended affine Lie algebras (EALAs) that generalize affine algebras. EALAs occur in families that are constructed from...

(iii) G is an ajfine group, that is, the socle of G is a vector space V, where V s= {ZpY for some prime p and n=p ; moreover, if Go is the stabilizer of the zero vector in V then G = VG0, Go is an irreducible subgroup of GLd(p), and GQ has exactly two orbits on the non-zero vectors of V. The rank 3 groups under (i) are given by the classification of the 2-transitive groups with simple socle (se...

In the finite-dimensional setting, every Hermitian-symmetric space of compact type is a coadjoint orbit of a finite-dimensional Lie group. It is natural to ask whether every infinite-dimensional Hermitiansymmetric space of compact type, which is a particular example of an Hilbert manifold, is transitively acted upon by a Hilbert Lie group of isometries. In this paper we give the classification ...

We present some elementary ideas to prove the following Sylvester-Gallai type theorems involving incidences between points and lines in the planes over the complex numbers and quaternions. (1) Let A and B be finite sets of at least two complex numbers each. Then there exists a line l in the complex affine plane such that |(A×B) ∩ l| = 2. (2) Let S be a finite noncollinear set of points in the c...

We begin by considering certain analogues, in finite 3-dimensional affine spaces, of the ordinary cube. From the properties of these structures (as geometric lattices having point sets which are threefold Cartesian products) we derive the notion of an (abstract) finite cube. By studying the additional properties (including the properties of certain groups associated with the cube) of members of...

Let X be a normal variety endowed with an algebraic torus action. An additive group action $\alpha$ on is called vertical if general orbit of contained in the closure and image normalizes Aut(X). Our first result this paper classification actions under assumption that proper over affine variety. Then we establish criterion as to when infinitesimal generators finite collection generate finite-di...