On the exactness of Kostant-Kirillov form and the second cohomology of nilpotent orbits
arXiv:1203.6018
Abstract
We give a criterion for the Kostant-Kirillov form on an adjoint orbit in a real semisimple Lie group to be exact. We explicitly compute the second cohomology of all the nilpotent adjoint orbits in every complex simple Lie algebras.
Final version