Almost conformally almost Fedosov structures

Abstract

We study the relations between the projective and the almost conformally symplectic structures on a smooth even dimensional manifold. We describe these relations by a single almost conformally symplectic connection with totally trace--free torsion sharing the geodesics (up to parametrization) with the projective class. This connection generalizes a (conformally) Fedosov structure depending on the remaining torsion of this distinguished connection. In fact, we see these structures as the almost symplectic analogy of the conformal Riemannian structures, because there is an analogy of the class of Weyl connections on the conformal Riemannian structure. Moreover, such a class encodes the variability of the connections in a projective class. The distinguished connection trivializes such a class of Weyl connection. There is a description these geometric structures as Cartan geometries that generalizes the description of projective and conformal Riemannian structures as parabolic geometries. This makes possible to construct an analogy of the so--called Bernstein-Gelfand-Gelfand sequences and Bernstein-Gelfand-Gelfand complexes.