Effective reduction of Goresky-Kottwitz-MacPherson graphs.
For a manifold endowed with a Legendrean (or Lagrangean) contact structure , we give an elementary construction of an invariant partial connection on the quotient bundle . This permits us to develop a naïve version of relative tractor calculus and to construct a second order invariant differential operator, which turns out to be the first relative BGG operator induced by the partial connection.
For a Fedosov manifold (symplectic manifold equipped with a symplectic torsion-free affine connection) admitting a metaplectic structure, we shall investigate two sequences of first order differential operators acting on sections of certain infinite rank vector bundles defined over this manifold. The differential operators are symplectic analogues of the twistor operators known from Riemannian or Lorentzian spin geometry. It is known that the mentioned sequences form complexes if the symplectic...
Let be a (generalized) flag manifold of a complex semisimple Lie group . We investigate the problem of constructing a graded star product on which corresponds to a -equivariant quantization of symbols into twisted differential operators acting on half-forms on . We construct, when is generated by the momentum functions for , a preferred choice of where has the form . Here are operators on . In the known examples, () is not a differential operator, and so the star product ...
A mistake was found in the reasoning leading to a Lagrangian which we considered as equivalent from the formula for the action S(γ) below the classical mechanical problem (3) on "Non singular Hamiltonian systems and geodesic flows on surfaces with negative curvature", page 271.