  Let \pi: Y -> X be a crepant projective resolution of an affine symplectic
variety X with a good C^*-action.
  We interpret the second cohomology H^2(Y, C) in two ways. First, H^2(Y, C) is
the Picard group of Y tensorised with C. By the ample cones of different
crepant resolutions of X, there is a natural chamber structure in H^2(Y, C).
The second interpretation of H^2(Y, C) is the base space of the universal
Poisson deformation $\mathcal Y$ of Y. Let D \subset H^2(Y, C) be the locus
where the corresponding Poisson varieties are not affine. Then D is the union
of finite number of hyperplanes, which gives a chamber structure in H^2(Y, C).
  These two chamber structures coincide.
