Let G be the group with Borel subgroup B, associated to a Kac-Moody Lie algebra [unk] (with Weyl group W and Cartan subalgebra [unk]). Then H(*)(G/B) has, among others, four distinguished structures (i) an algebra structure, (ii) a distinguished basis, given by the Schubert cells, (iii) a module for W, and (iv) a module for Hecke-type operators A(w), for w [unk] W. We construct a ring R, which ...

A new formulation of Calogero-Moser models based on root systems and their Weyl group is presented. The general construction of the Lax-pairs and the proof of the integrability applicable to all models based on the simply-laced algebras (ADE) are given for two types which we will call ‘root’ and ‘minimal’. The root type Lax pair is new; the matrices used in its construction bear a resemblance t...

The classical Airy function has been generalised by Kontsevich to a function of a matrix argument, which is an integral over the space of (skew) hermitian matrices of a unitary-invariant exponential kernel. In this paper, the Kontsevich integral is generalised to integrals over the Lie algebra of an arbitrary connected compact Lie group, using exponential kernels invariant under the group. The ...

We consider Yang-Mills theories with general gauge groups G and twists on the four torus. We find consistent boundary conditions for gauge fields in all instanton sectors. An extended Abelian projection with respect to the Polyakov loop operator is presented, where A 0 is independent of time and in the Cartan subalgebra. Fundamental domains for the gauge fixed A 0 are constructed for arbitrary ...

The reductions for the first order linear systems of the type: Lψ(x, λ) ≡ ( i d dx + q(x)− λJ ) ψ(x, λ) = 0 , J ∈ h , q(x) ∈ gJ are studied. This system generalizes the Zakharov–Shabat system and the systems studied by Caudrey, Beals and Coifman (CBC systems). Here J is a regular complex constant element of the Cartan subalgebra h ⊂ g of the simple Lie algebra g and the potential q(x) takes val...

Using the geometric Satake correspondence, Mirkovic-Vilonen cycles in affine Grasssmannian give bases for representations of a semisimple group G . We prove that these are perfect, i.e. compatible with action Chevelley generators positive half Lie algebra g. compute this terms intersection multiplicities Grassmannian. stitch together to basis C[N] regular functions on unipotent subgroup. multip...

The n-dimensional (isotropic and non-isotropic) harmonic oscillator is studied as a Wigner quantum system. In particular, we focus on the energy spectrum of such systems. After briefly recalling the notion of a Wigner quantum system, we show how to solve the compatibility conditions in terms of osp(1|2n) generators, and also recall the solution in terms of gl(1|n) generators. We then go on to d...

The classical Airy function has been generalised by Kontsevich to a function of a matrix argument, which is an integral over the space of (skew) hermitian matrices of a unitary-invariant exponential kernel. In this paper, the Kontsevich integral is generalised to integrals over the Lie algebra of an arbitrary connected compact Lie group, using exponential kernels invariant under the group. The ...

The n-dimensional (isotropic and non-isotropic) harmonic oscillator is studied as a Wigner quantum system. In particular, we focus on the energy spectrum of such systems. We show how to solve the compatibility conditions in terms of osp(1|2n) generators, and also recall the solution in terms of gl(1|n) generators. A method is described for determining a spectrum generating function for an eleme...

Let 9 be a reductive complex Lie algebra, with adjoint group G, Cartan subalgebra ~ and Weyl group W. Then G acts naturally on the algebra of polynomial functions &'(g) and hence on the ring of differential operators with polynomial coefficients, .97(g). Similarly, W acts on ~ and hence on .97(~). In [BC2], Harish-Chandra defined an algebra homomorphism J : .97(g)G -t .97(~)w. Recently, Wallach...