Poisson deformations and birational geometry
Algebraic Geometry
2014-04-08 v6
Abstract
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 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.
Cite
@article{arxiv.1305.1698,
title = {Poisson deformations and birational geometry},
author = {Yoshinori Namikawa},
journal= {arXiv preprint arXiv:1305.1698},
year = {2014}
}
Comments
15 pages, the title of the article is slightly changed