LAUSR

Abstract In the framework of Banach differential geometry we investigate the fiber-wise linear Poisson structures as well as the Lie groupoid and Lie algebroid structures which are defined in the canonical way by the structure of a W ∗ -algebra (von Neumann algebra) M . The main role in this theory is played by the complex Banach–Lie groupoid G ( M ) ⇉ L ( M ) of partially invertible elements of M over the lattice L ( M ) of orthogonal projections of M . The Atiyah sequence and the predual Atiyah sequence corresponding to this groupoid are investigated from the point of view of Banach Poisson geometry. In particular we show that the predual Atiyah sequence fits in a short exact sequence of complex Banach sub-Poisson V B -groupoids with G ( M ) ⇉ L ( M ) as the side groupoid.