Let M2n be a Poisson manifold with Poisson bivector field Π. We say
that M is b-Poisson if the map Πn:M→Λ2n(TM) intersects the
zero section transversally on a codimension one submanifold Z⊂M. This
paper will be a systematic investigation of such Poisson manifolds. In
particular, we will study in detail the structure of (M,Π) in the
neighbourhood of Z and using symplectic techniques define topological
invariants which determine the structure up to isomorphism. We also investigate
a variant of de Rham theory for these manifolds and its connection with Poisson
cohomology.Comment: 34 pages. Some changes have been implemented mainly in Sections 2 and
6. Minor changes in exposition. References have been adde