Star products on generalised complex manifolds

We regard classical phase space as a generalised complex manifold and analyse the B-transformation properties of the *-product of functions. The C*-algebra of smooth functions transforms in the expected way, while the C*-algebra of holomorphic functions (when it exists) transforms nontrivially. The B-transformed *-product encodes all the properties of phase-space quantum mechanics in the presence of a background magnetic field.